Fish Articles

Cheat Sheet / Updated 02-24-2022

To start and keep a freshwater aquarium, you need not only a tank, but the other equipment necessary to keep the water habitable for the fishy inhabitants. When you purchase those fish, make sure that you go to a good dealer and that you buy healthy fish. And when those healthy fish get sick, as some may, tap into the simple remedies in this Cheat Sheet to help restore them to health.

Cheat Sheet / Updated 03-12-2021

Keeping a saltwater aquarium means maintaining a fairly strict maintenance schedule to keep the life inside healthy. The water in saltwater aquariums requires regular testing for a variety of minerals and chemical balances. Figuring out the right feeding schedule and amount for your fish is a task that needs attention when you first stock your aquarium and when the population changes.

Article / Updated 12-30-2019

Is there anybody who doesn’t like going to a big public aquarium? I don’t think so. You can see and discover so much at an aquarium, and there’s usually not enough time to see it all in one day. For the home aquarist, the large public aquarium is also a great place to see just how a healthy aquarium should look. These places are loaded with information about fish, invertebrates, marine mammals, reptiles, and amphibians. Don’t be afraid to steal an idea or two about aquarium decoration, species composition, and the re-creation of natural settings. I’ve been to public aquariums all over the United States; here are a bunch that I really liked. This is in no way a comprehensive list of aquariums, just a smattering. No matter where you live, there’s an aquarium not too far away. So, if you don’t see one close to you listed here, poke around online and you’ll find one. New England Aquarium Since I’m from the northeast and still live there, the New England Aquarium in Boston, Massachusetts, was one of the first large public aquariums that I ever visited. In fact, I dare say that the Giant Ocean Tank loaded with all kinds of fishes, including sharks, helped to inspire me to become a marine biologist and home aquarist. Check it out online as well. Mystic Aquarium Located in, you guessed it, Mystic, Connecticut, this aquarium not only houses all kind of fish and invertebrates, but it’s well known for its incredible display of beluga whales. You can start your visit to Mystic Aquarium online. National Aquarium The next time you’re kicking around the beautiful waterfront in Baltimore, Maryland, you should make it a point to visit the National Aquarium. This aquarium is chock-full of all kinds of animals including birds, amphibians, and reptiles; it also has an incredible dolphin amphitheater. Georgia Aquarium Touted as the largest aquarium in the world, the Georgia Aquarium in Atlanta is an incredible facility with more than eight million gallons of saltwater and freshwater and more than 120,000 animals representing 500 species. One of the highlights of the aquarium is the Ocean Voyager gallery, which allows you to view the largest fish species in the world, the whale shark, through a 100-foot underwater tunnel. SeaWorld The SeaWorld name is synonymous with ocean-oriented parks and combines animal attractions with rides, shows, dining, and shopping. With parks in Orlando, Florida, San Antonio, Texas, and San Diego, California, SeaWorld offers a little of everything for everyone, including that oddball family member that doesn’t like fish. Tennessee Aquarium Now, granted, people usually don’t think of Chattanooga, Tennessee when it comes to saltwater, but the Tennessee Aquarium has a fantastic collection of marine animals. Also, this may a book for the saltwater enthusiast, but freshwater counterparts are people, too, and the Tennessee Aquarium is among the largest freshwater aquariums in the world. Audubon Aquarium of the Americas How do you combine great music, fantastic food, and marine life? You go to the Aquarium of the Americas in New Orleans, of course. Having conducted research in the bayous of Louisiana, I can tell you that these unique habitats house some of the toughest critters in the world, like bull sharks, alligator gars, and catfishes. But you don’t have to brave the mosquitoes to see all these critters and more if you drop by this aquarium. Monterey Bay Aquarium Located in a quaint, historic Monterey, California, this aquarium offers a phenomenal and incredibly natural re-creation of Pacific marine habitats and their inhabitants. With exhibits ranging from kelp forests to the open ocean, this aquarium has all kinds of Pacific fishes and animals including sea otters and penguins. My personal favorite is the Open Sea exhibit, which houses giant bluefin tuna, ocean sunfish, and the scalloped hammerheads. See more of the Monterey Bay Aquarium at their website. Shedd Aquarium A trip to Chicago wouldn’t be complete without a visit to the Shedd Aquarium. Touted as one of the largest indoor public aquariums, Shedd Aquarium has been around since 1930 and currently houses more than 30,000 animals. Don’t let its location fool you; there are plenty of saltwater exhibits with an amazing assortment of marine animals from sharks to whales. The Seas with Nemo and Friends Formerly called The Living Seas at Walt Disney World, The Seas with Nemo and Friends aquarium is a great way to cap off a family vacation at this amazing resort. Based on the popular fish-related movie, Finding Nemo, this aquarium combines entertainment with aquarium viewing. Visitors board Clamobiles and venture into the sea with popular characters of the film, then view all kinds of tropical fishes, dolphins, manatees, and sharks in the main pavilion.

Article / Updated 12-30-2019

The biggest questions when it comes to feeding your saltwater aquarium fish are how much and how often to feed them. Some fish are gluttons, whereas others stop when they’re full. You probably know people from both ends of this spectrum. Have the same person or people feed the aquarium. This ensures that the feeding is done consistently and with an eye for the right quantities. Letting Uncle Bill feed the fish when he visits may result in a lot of waste and water pollution. Also, keep a tight lid on the tank during a party. Inevitably, everybody wants to feed the fish. Feeding them too little is better than too much. Use the following guidelines when feeding and you’ll develop a working sense of how much and how often to feed them. Offer as much food as your fish will eat in five minutes. Flakes should sink no deeper than one-third the height of the tank. Provide tablets, pellets, or sinking food for bottom fish and invertebrates. Feed your fish in very small portions over the five-minute period. If any food is left over after this time, you’re an overfeeder. Bear in mind, however, that some foods, such lettuce or spinach, are nibbled over time, so the five-minute rule doesn’t apply to leafy vegetables. Some foods can be attached to the side of the tank with a food clip, as shown. If you’re home during the daytime, feed your fish and invertebrates very small portions over the course of the day. In this case, reduce feeding time to about a minute or two per session. If you’re not home, feed them twice a day at the same times every day: once in the morning, once in the evening. Always feed your fish at the same spot in the tank. Doing so lets you sneak food down to bottom-dwellers while the surface fish are distracted. Rehydrate or thaw food beforehand. Use a separate container, such as a glass. Don’t overfeed the fish, no matter how much you think they need more food. Overeating stresses your fish and causes detritus to accumulate in the tank, degrading water quality. Deal with the oddballs You’ll find a lot of exceptions when feeding your wet pets. For example, some invertebrates, such as sea anemones and corals, house photosynthetic bacteria that provide them with nutrients, so you don’t need to feed them every day. Their diet, however, should be augmented once or twice a week with fresh, frozen, or live foods. Also, large carnivorous fish typically consume one large meal at a time, so you don’t need to feed them more than once every day or two. It’s better to underfeed than to overfeed your fishes and invertebrates. Keep a watchful eye Watch all your fishes during feeding. During this time, you can also assess your fishes’ health and take a head count. Try to make sure that each gets its share of food, but that’s not always possible. In the ocean world, it’s eat or go hungry, so don’t expect a lot of goodwill. Remember that fish have different mouth shapes, which allow them to feed at different levels in the tank. Some species don’t move to the surface to eat; they wait for food to disperse throughout the tank. Don’t rely on surface feedings and the leftovers of others to feed bottom fish. Pellets or other foods that sink to the bottom should be provided to these fish. You may have to offer food through a turkey baster or distribute food via a feeding stick. Refusal to eat is one of the first signs of illness, so keep an eye out for fish that seem to have no interest in food. Always remove food from the tank that hasn’t been consumed. Allow nibblers time to eat — an hour or two — before removing leftovers. Offer a variety Freshwater fish and saltwater fish aren’t the same — you know that. If you’ve ever had a freshwater aquarium, more than likely you sprinkled just dry flake food in your tank every day. You need to break that habit. Although you can offer a daily staple, variety is the spice of life for marine organisms. You can try flake food and frozen brine shrimp as your staples, but mix in different foods as your fish acclimate to your aquarium. Try not to feed your fish right after turning on the light, because they won’t be fully alert until about 30 minutes later. In addition, make sure you match the size of the food with the size of the fishes’ mouths. You may need to crush or mulch the food for fish with small mouths. But don’t grind the food too small. Doing so adds fine particles to the water that aren’t ingested and that degrade water quality. What to do when you're going away If you’re going to be away from your aquarium for one or two days, the fish will be fine without food. In the wild, most fish feed sporadically and can go days without food, so a little fasting doesn’t hurt them. When you return, don’t feel that you have to feed your fish twice as much because they missed a meal. If you do, much will go uneaten. If you plan to travel for longer periods, you have a couple of options: You can arrange for someone to feed your fish. Prepare portions ahead of time and give detailed instructions on how to properly feed your animals. Don’t let her do so at her own discretion unless she’s an experienced aquarist. You can purchase an automatic feeder. This specialized piece of equipment dispenses dry food for you while you’re away. You wouldn’t want to load it with fresh seafood, but many processed foods work well. Test your automated feeder before going away. A feeder that is set up improperly or malfunctions can be deadly to your aquarium. Nobody wants to come home to dead pets.

Article / Updated 12-30-2019

Cleaning an aquarium involves a conscientious effort on your part. In fact, maintaining a fish tank isn’t for the lazy at heart. Don’t set up a saltwater aquarium if you don’t intend to follow through and keep it clean and healthy. All too often, an aquarist’s interest wanes after the first couple of months of ownership, and the aquarium occupants ultimately suffer the consequences. Realize that going into this hobby requires a real commitment on your part. You need to show concern at every step and on every level. Your fishes’ lives depend on your attention to detail. If you’re a parent, and your children have an aquarium, it’s your responsibility to help them maintain the aquarium. You probably experienced the empty promises made by children who want a new pet. Make a game out of it and try to keep it fun. As soon as it starts to feel like work, you’re on your own. Basic tasks need tended to on a regular basis. They’re listed as follows, and I cover them in detail in the following sections: Vacuum the gravel. Clean and maintain the filters. Test your water quality. Conduct partial water changes. Customize the schedule as you see fit. The frequency with which you clean your aquarium depends on how dirty it gets, and that depends on the number of occupants, the quality of your filtration, and the amount of food that is left to foul your tank. How to vacuum your saltwater aquarium Vacuuming is one of the most important parts of maintaining your tank. You must reduce the accumulation of detritus in the gravel so that your biological filters aren’t overwhelmed. Detritus is the combination of fish wastes and uneaten food that sinks to and decays on the bottom of the aquarium. If not removed, this organic waste breaks down into ammonia and overwhelms the nitrogen cycle. This will, in turn, disturb your water chemistry, snowballing into a series of problems that will ultimately harm your fish and invertebrates. Detritus can be particularly damaging to an undergravel filter. Too much clogs the undergravel filter, preventing water flow through the gravel and reducing the filter’s ability to do its job. Although an aquarium vacuum is a nice piece of equipment, the old-fashioned garden hose also works to siphon wastes (see the section “Siphoning water” later in this chapter). If you choose to purchase an aquarium vacuum, sometimes called a substrate cleaner, more than likely you can find them at your aquarium dealer. The most efficient way to vacuum your aquarium is while conducting a water change, because water is removed in the process anyway. This accomplishes two goals at once: Vacuuming detritus Removing water from the tank for replacement When you vacuum, make sure you gently rake the gravel. If you have an undergravel filter, don’t mix it up too aggressively or you will disrupt the filter bed. How to clean saltwater aquarium filters Many filters have their own maintenance schedule. The level to which you clean your filter depends on the kind of filtration that it provides. A filter that’s strictly mechanical can be cleaned thoroughly to remove debris, whereas a biological filter shouldn’t be touched except to remove large detritus. Somewhere in the middle is the chemical filter, which should be recharged every month. Filters remove wastes from the aquarium and either retain them (mechanical and chemical filtration) or convert them to less harmful compounds (biological filtration). With the exception of the natural biological filtration of live rock, wastes accumulate in most filters until you remove them by cleaning. In the following sections, I touch briefly on each filter, giving you a maintenance routine. Inside box filter Although you may not be using inside box filters except in a quarantine tank (see Chapter 5), you can easily maintain them. Simply replace the activated carbon and the filter floss every month, retaining about half of the latter for the bacteria that they harbor. Sponge filter Because the sponge in this type of filter provides the filter medium for mechanical and biological filtration, there are no other media to change. Sponge filters are easy to maintain by rinsing them in water every two weeks to a month, but be careful not to wash them out too thoroughly (keep those bacteria!). Undergravel filter After a healthy undergravel filtration system is established, this filter can be used indefinitely without being disassembled and cleaned. There is no filter floss or carbon to change, and the only medium is the gravel itself. Nonetheless, debris does accumulate in the gravel, so the gravel needs to be vacuumed to keep the filter from clogging. Vacuum during routine partial water changes every two weeks. Every month, make sure that you check the airstones that power your undergravel filter and replace them if they’re clogged or crumbling. If you have powerheads, make sure the intakes are clear and the impeller inside is clean. I like to take them apart every month and clean the moving non-electrical parts under running tap water. If they have excessive buildup of coralline algae, soak them and other fixtures in white vinegar for a couple of hours; doing so will dissolve the calcium. Power filters Power filters are easy to maintain. Most have cartridges that can be replaced every two to four weeks, depending on bioload and waste accumulation. However, make every effort to retain 50 percent of the used filter media or use a sponge type medium so helpful bacteria aren’t lost. If your filter has two cartridges, alternate their replacement so bacteria are always present. Activated carbon should be replaced every month, as well. If your filter is equipped with a biowheel, you can retain bacteria even though you have to replace the internal filter media. Biowheels don’t need to be cleaned. Filter impellers should be cleaned every month under running tap water so that they continue to run efficiently. Canister filters The canister filter contains compartments with various kinds of filter media, like activated carbon, filter sponges, filter floss, and ceramic bodies. The use of multiple filter media allows valuable bacteria to be retained when the filter is cleaned every month, depending on waste accumulation and bioload. When the canister filter is cleaned, the activated carbon is replaced, the ceramic bodies and filter sponges are rinsed and retained, and 50 percent of the filter floss is replaced. The number of filter components depends on the brand of canister filter — many are available. Read the manufacturer’s instructions and follow its recommended maintenance schedule. Don’t forget to check those impellers and clean them, as well. Trickle filters and sumps Trickle filters offer great advantages over other filter systems relative to filtration efficiency and effectiveness. In addition, they require little maintenance. Like the canister filters, you can find many brands, and the level to which you clean them depends on their components. Every month, replace the carbon and rinse the sponges and filter pads that are providing mechanical filtration. Bioballs and ceramic bodies can be rinsed every six months to a year. Live rock The natural biological filtration of live rock needs little to no maintenance. As long as the aquarium remains healthy and circulation is maintained, live rock is self-cleaning and self-perpetuating. That’s why this natural choice of filtration is becoming so popular. Protein skimmers Daily checks are required for the protein skimmer to make sure that it’s working properly and to empty the collection cup if needed. Airflow components, like airstones, air ports, and tubing, should be checked regularly and then cleaned and replaced as needed. Every month, clean the powerhead or water pump impellers, as well. Follow your manufacturer’s maintenance schedule so that your protein skimmer is kept running efficiently. Testing, testing, testing (your water) When you first set up your aquarium, testing the water every day is critical to monitoring the water-maturation process. As you begin to add fish, water chemistry will change radically, and water-quality monitoring remains essential for the survival of your fish. After this sensitive period, which can last several weeks, it’s still important to test your water. I recommend that you do so at least once every week. Doing so gives you a good understanding of the mechanics of the nitrogen cycle and tells you when the nitrates, carbonate hardness, pH, and other parameters are to the point at which a water change is needed. As for temperature and specific gravity/salinity, you should keep an eye on those parameters every day. Look out for sudden behavioral changes in your fish, fish disease, fish mortality, excessive algal growth, smelly water, and cloudy water. All these warrant an immediate water-quality test and possible water change. Keep track of the results of your water testing in a journal so you can compare them to previous test results. If you notice a dramatic change since the last test in any water parameter, you may need to conduct a water change or make adjustments. How to change the water Water changes are one of the most important aspects of cleaning and maintaining your aquarium. Waste products build slowly in your aquarium and the resilience of your water is slowly depleted. The only way to solve both of these problems is to physically change your water, removing the wastes and replenishing valuable trace elements. How much water and how often do you change it? The typical preventative water change usually involves 10 to 20 percent of the tank’s volume being replaced with properly balanced premixed seawater. The added water, which should be the correct specific gravity and temperature, will also replace exhausted trace elements and nutrients. The amount you change varies with the quality of your water, the aquarium’s bioload (number of critters), and the frequency of water changes. Most experts recommend a 10 percent water change every week or a 20 percent change every two weeks. If your aquarium is crowded, your son Wilson has a tendency to overfeed the fishes, or you’re unable to change your water frequently, you may need to change a greater volume. However, if your aquarium isn’t heavily stocked, you’re careful when you feed, and you’re religious about water changes, you can get away with less. I recommend that you start with a water change of 20 percent every two weeks and modify it either up or down depending on the type of filtration and water quality. For example, a 55-gallon saltwater aquarium with live rock or a trickle filter (wet/dry filter) and a protein skimmer can probably go longer between water changes. Keep an eye on nitrate levels because they tell you if you need to increase or decrease the frequency and volume of water changes. How to siphon water The best way to conduct a water change is to use an aquarium vacuum and a large plastic bucket. The vacuum has a large diameter tube attached to a siphon. The siphon is used to draw water from the aquarium, while the vacuum is thrust into the substrate, stirring the gravel and allowing detritus to flow out with the water into the bucket. The surface gravel should be stirred during every partial water change for two reasons. If you have an undergravel filter, stirring breaks up impacted areas in the filter bed where water flow has become restricted. Stirring puts detritus into suspension where it can be siphoned out with the old water. When you change the water, make every effort to efficiently cover as much of the substrate as possible, but don’t rush over spots. If you can’t cover it all, make a mental note where you left off and start at that spot with the next water change. If your substrate is sand, only move the vacuum over the top of the sand and be careful not to suck it right out of the tank. These steps explain how to siphon: Fill the tube completely with water, making sure no air is trapped in the tube. Ensure the siphon and your hands are clean. You can fill the hose by submerging it in the aquarium, but do this only if your aquarium is large enough to accommodate the hose without spooking the fish. Otherwise, place one end of the tube in the tank, put your mouth on the other, and draw the aquarium water that way to start the flow. Make sure the bucket end is lower than the aquarium, or siphoning won’t work. If you filled your siphon in the aquarium, plug one end of the hose tightly with your thumb, lift it from the aquarium, and bring it lower than the tank to the bucket. Release your thumb, and the water will begin to flow rapidly from the aquarium into the bucket. You can control the water flow by pinching the hose. Discard the water in the bucket. The following figure illustrates both siphoning water to and from the tank. How to add water When you need to add water, make sure you use premixed and conditioned saltwater that you store in a cool, dark place. Heat your replacement water to the same temperature as your aquarium and aerate it for about 15 minutes before conducting the water change. To add water, pour the premixed saltwater slowly into your tank, making sure not to disrupt the aquarium or its inhabitants. Verify the water you add is the same temperature and specific gravity as the water in your aquarium. Water out of your tap may be loaded with chlorine, chloramine, heavy metals, phosphates, and other ions. Many of these compounds are harmful to fish, so they need to be removed. This process is called water conditioning. It doesn’t hurt to read the water-mixing sections in Chapter 9 to review how to premix and condition salt water. Your local water company routinely checks the water supply for these compounds. Check with them to find out what’s in your tap water. How to top off your aquarium Don’t confuse water changes with adding water that has evaporated from the aquarium. Depending on the amount of aeration and circulation that you have, you may have more or less water evaporation. When water evaporates, dissolved salts are left behind, and the specific gravity of the water increases. Pay attention to this process, because changes in specific gravity cause severe problems for your tank’s inhabitants. Water evaporation is readily solved by adding freshwater, not premixed conditioned saltwater, to your aquarium. The water you add should be conditioned tap water. If you don’t have a lot of evaporation, the use of store-bought distilled water relieves you of the need to condition the water. Distilled water is pure water, that is, pure H2O without additives and toxic compounds. Many aquarium shops sell filtered water specifically for saltwater aquariums.

Article / Updated 12-30-2019

One thing is certain, not all algae are alike. Although a number of formal classifications have been set up for algae, and scientists recognize at least eight major divisions, not all occur in the typical aquarium. Some kinds are desirable, and others are not. Some are typically referred to as seaweeds, others are planktonic, and some are both. There is really no point in reviewing all the various kinds of algae, so the following sections concentrate only on those that you’re most likely to encounter or purchase for your marine aquarium. Green algae Traditionally called the Chlorophyta, green algae have now been technically separated into several taxonomic groups, but green algae is a much easier term to remember. With more than 7,000 species, this group of algae is the most diverse, but only about 10 percent of the green algae are marine forms. These are typically the most beneficial of the algae, although some species are less desirable. They’re green in color because their chlorophyll pigments are identical to those of higher plants. Although many green algae are seaweeds, the planktonic spores of some species aren’t visible to the naked eye but appear as a green cloudiness in the water. These algae sometimes form a green film on the aquarium glass. Larger green algae species may come in desirable plantlike shapes or less desirable hair and mat-like forms. The most attractive species of green algae are cultivated and sold as attractive additions to your aquarium. The following types of green algae are popular: Caulerpa: This is the most popular and common genus of green algae in the aquarium (see the following figure). Members of this group come in a variety of colors ranging from lime green to bluish brown. They typically have a single stalk with blade-like leaves. These prolific algae are cultivated and offered by many marine aquarium dealers. Chaetomorpha: Typically referred to as Chaeto, spaghetti algae, or green hair algae, these hair-like algae remove phosphates and nitrates from the water. This algae are an excellent macro-algae for the refugium, but don’t introduce them into the main aquarium. Halimeda: Unlike the Caulerpa, members of this genus are calcareous, meaning they contain calcium. They resemble underwater cacti growing as a series of circular flat plates. After death, the white calcium from these algae contributes to the sparkling white sand that you see on Caribbean beaches. In the aquarium, they’re indicative of a healthy environment. Ulva: Commonly referred to as sea lettuce, this group contains excellent algae for the refugium where they consume nitrates and phosphate. These leafy green algae are nutritious and readily accepted by herbivorous fish as well as invertebrates. Valonia: These species of algae are called bubble algae because they form clusters of spherical bubbles. Although they have an attractive silver appearance, bubble algae can overgrow an aquarium and should be watched closely and regularly cropped. Hair algae are less desirable. These algae form thick, hair-like mats that can carpet your aquarium. For a fish-only tank, this matting will be simply ugly, but in the reef tank, it can smother and kill live corals. Make efforts to control hair algae in the main aquarium. Red algae This group of algae, called the Rhodophyta, contains more than 7,000 species, and many are marine seaweeds. Although most red algae are multicellular and grow attached to rocks and other algae (see the following figure), some are single-celled forms. Red algae are red because of the pigment called phycoerythin, which absorbs blue light and reflects red light. Their coloration, which depends on how much of this pigment they have, ranges from reddish yellow to bright red to greenish blue and brown. Because blue light penetrates much deeper than red light, these algae typically live at deeper depths and are well adapted to low lighting conditions. A lot of red algae are introduced into the aquarium on live rocks. The most common are called coralline red algae, which secrete a hard calcareous shell the way corals do. These algae are considered important in the formation of tropical reefs and, in some areas, may contribute more to reef structure than corals. They’re beneficial to an aquarium, encrusting rocks and even spreading to the fixtures and glass. Brown algae Belonging to the class Phaeophyceae, the brown algae comprise about 2,000 species that are predominantly marine seaweeds. There are no single-celled forms of brown algae (the simplest is a branched filamentous organism, which is technical information that you don’t need to remember). Their brown coloration results from the dominance of a xanthophyll pigment, which masks other pigments including chlorophyll. Colors of brown algae range from pale beige to yellow-brown to almost black. The most common brown algae, called kelp, are the largest algae, the ones that attain lengths greater than 200 feet. The giant kelp forms expansive seaweed forests off the coast of North America and provides habitat and shelter for many organisms. Tropical waters have fewer species of brown algae. Some forms of brown algae come attached to live rock when you purchase it. Like the red algae, small amounts of brown algae are generally beneficial for a saltwater aquarium. Diatoms Sometimes referred to as brown algae because of their coloration, diatoms are microscopic cells composed of overlapping half shells of silica. The diatoms are planktonic and benthic (live on the bottom) algae that spend their lives floating in the ocean or in the sediments. Their silica shells, called frustules, are remarkably geometric in shape, but their microscopic size makes them difficult for the average aquarist to see. In the ocean, diatoms form a major part of the plant-plankton called phytoplankton, providing important food for the animal-plankton called zooplankton. These algae proliferate in aquariums with high nitrate levels. They’re usually the first algae to establish themselves. Diatoms form a brown slime on the gravel, rocks, decorations, and aquarium glass (see the following figure). Heavy concentrations of diatoms discolor the water. As the aquarium matures, these algae should disappear. Until they do, you can scrape them away to keep a clear view of your aquarium pets. Dinoflagellates Members of this group are single-celled organisms that have the characteristics of both plants and animals (refer to the following figure), but they’re still considered algae. Although it sounds like a prehistoric reptile, the name dinoflagellate actually refers to their forward swimming motion created by their tails, which are called flagella. Not all species of dinoflagellates are photosynthetic, and some species are planktonic, while others are benthic; that is, they live on the bottom. Some species of dinoflagellates are harmful to sea life and those that eat it. Dinoflagellate blooms, called red-tide, turn coastal waters reddish-brown, producing serious toxins that can affect human health. Dinoflagellates can be both dangerous and healthy for your aquarium. Some kinds actually thrive when you have very low nutrient levels —little to no nitrates and phosphates — in your aquarium. These dinoflagellates are able to harness light and photosynthesize their own food, allowing them to overrun your aquarium and create a brown slime. If this happens, you can use commercial remedies, physically remove the algae, reduce flow in your aquarium, introduce competitive organisms like live rock, and turn off the skimmer. Those dinoflagellates that utilize aquarium nutrients are good for your aquarium, as long as they aren’t allowed to proliferate out of control. In some instances, excessive nutrient levels cause dinoflagellate blooms in your aquarium. If this happens, the algae must be physically removed with a siphon. The best defense against dinoflagellates is to maintain a proper biological balance in the aquarium and avoid situations of extreme cleanliness. The dinoflagellates that are of greatest interest to aquarists are those that live in live corals, sponges, clams, and anemones. These are called zooxanthellae, and I discuss them in Chapter 4. These algae form a symbiotic relationship with their hosts, providing beneficial organic carbon that they produce by photosynthesis. If you’re an invertebrate enthusiast, make sure you have sufficient lighting to keep zooxanthellae dinoflagellates alive. If they die, in all likelihood, their host will die. Blue-green algae The blue-green algae are technically not algae at all: They are bacteria. For years, they were considered algae because they’re aquatic and make their own food. This group of bacteria is called the Cyanobacteria, and it has the distinction of being the oldest known group of organisms at more than 3.5 billion years old. Because they’re bacteria, blue-green algae are small and single-celled, but they grow in large enough colonies that you can see them. Although called blue-green algae, they can have colors ranging from black to red to purple. They may be earth’s bacterial heroes, but when these algae are in your aquarium they can be both good and bad. Like a lot of bacteria, blue-green algae in your substrate are beneficial to the health of your aquarium, feasting on detritus (organic wastes). However, in cases of poor water quality, high nutrients, and poor circulation, they form a dark brownish-red gelatinous mat, called red slime, on rocks, gravel, and plants in your tank. They’re also capable of producing toxins that poison aquarium fish. If allowed to proliferate, they smother the tank. Unfortunately, few critters feed on blue-green algae, so they must be physically removed with a siphon during a partial water change. Several products on the market help eliminate slime algae, but the key is to stay on top of your water chemistry, water changes, and water circulation.

Article / Updated 12-30-2019

Fish and invertebrates are living creatures that require food for energy, burning it with the help of oxygen that they respire (breathe from the water). These processes produce waste products that are returned to the environment through the gills and in the urine and feces. These wastes are primarily carbon dioxide and nitrogenous compounds (like ammonia), which are extremely toxic to fish. In the aquarium, these wastes must be removed. Carbon dioxide (CO2) generally leaves the water through water circulation and aeration at the surface or through photosynthesis by aquarium algae. Ammonia, on the other hand, must be converted to nitrite, which is then converted to nitrate, a less toxic compound. This conversion of harmful ammonia into nitrite and then nitrate is called the nitrogen cycle. Why do you need to know about the nitrogen cycle? Because it’s the basis of biological filtration, and your filters use biological filtration to keep your aquarium clean. Without biological filtration, your aquarium won’t survive! Your marine animals aren’t the only source of nitrogenous wastes. Every time you feed your pets, excess food will decompose into harmful compounds, including ammonia. That is why you need to make every effort to feed your fish carefully so as not to leave excess food in the aquarium. Before you can fully stock an aquarium, you need to establish the nitrogen cycle. The following sections help you do so. The role of bacteria in the nitrogen cycle A healthy aquarium depends greatly on the nitrogen cycle to reduce toxic ammonia into less-toxic nitrogen compounds. In your aquarium, ammonia builds slowly but decreases as it’s converted to nitrite. Then as the nitrite is converted to nitrate, nitrite decreases, and nitrate slowly accumulates. Ultimately, your healthy aquarium will have consistently low levels of ammonia and nitrite, while nitrate slowly builds. Biological filtration is actually bacteriological filtration. Believe it or not, the nitrogen cycle is driven by bacteria. Bacteria that convert ammonia (NH4) into nitrite (NO2) belong to the genus Nitrosomonas. Nitrite, in turn, is converted into nitrate (NO3) by bacteria of the genus Nitrobacter. These processes together are called nitrification. You may be wondering what happens to the nitrate. Well, nitrate will be assimilated by algae, and it will be converted to nitrogen gas by denitrifying bacteria. In most aquarium systems, however, nitrate slowly accumulates in the water because these two processes generally can’t keep up with nitrate production. Although nitrate is relatively harmless to fish, it must eventually be removed or diluted before toxic levels are reached. You do this with frequent water changes (removing a portion of the aquarium water and replacing it with fresh batches of premixed salt water). How to test the nitrogen cycle The nitrogen cycle needs to be established in a biological filter, which is a requirement for all marine aquariums. Even with a properly functioning biological filter, however, you want to frequently monitor the levels of ammonia, nitrite, and nitrate. You do this with commercial test kits that are available at your fish dealer. With the test kits, you can watch the cycle as it develops in your aquarium, and you’ll see your aquarium mature. I discuss what a mature aquarium looks like in the next section. Keep in mind that most serious fish dealers provide free water testing. Take full advantage of this service, because it allows you to compare the dealer’s results with those that you’re getting at home. Write down and date the results of your water testing so that you can follow the nitrogen cycle. Figure 12-2 shows an example of what my records look like. Feel free to model yours after mine. By keeping these records, you’ll know when the cycle is firmly established in your aquarium. I even plot my results in a spreadsheet program, so I can see the rise and fall of ammonia and nitrite — I guess that makes me officially a fish geek. Some websites and apps are available where you can post your test parameters; they even make the charts for you.

Article / Updated 11-23-2019

Before you’re ready to purchase freshwater fish for your aquarium, you need to know how to take care of the fish you want. You also need a general idea of the type of fish you’ll buy so that you know what types of plants and other items you need and how to set up water conditions that are just right for the species you choose. This discussion helps you get begin. Differences in species A fish’s physical makeup (fin shape and size, body shape, color, and so on) and how a fish uses its body in its natural environment is important when determining what type of fish and what type of aquarium you need for that particular species. For example, long, thin, streamlined fish such as danios tend to be speedy horizontal swimmers and love a tank that is long and not tall. Become familiar with the physical makeup of various aquatic species so that you can understand what system your fish will enjoy most. You can quickly see whether there is a problem, such as stress or disease, by observing any deviation in your fish’s normal body shape, fin shape, and swimming patterns. Knowledge isn’t only power; it’s also the best preventive method on earth for diagnosing aquarium problems before they get out of hand. Which types of fish are best for you You have so many choices in aquarium fish that you may wonder, where is the best place to start? There are many popular and easy-to-keep aquarium fish; you should have many good options to choose from when you begin. There are some excellent choices for beginning hobbyists. These fish are inexpensive, easy to find, forgiving of beginner mistakes, and will help get any aquarium off to a good start. You also can find a few neat invertebrates (animals that don’t have a spine) to keep your fish company. Buying fish — what you need to know The best way to start as a beginning fishkeeper is to develop a good relationship with a local pet store. A quality vendor can help you make decisions on the best way to set up or improve your system. She can also make good suggestions on fish compatibility and lend a hand if your fish become ill. The Internet is a great place to find fish, plants, and equipment for your new aquarium, but nothing beats the wonderful feeling of walking through a tropical fish store and seeing everything up close with a helpful dealer at your side. Aquarium clubs and societies are another good place to find aquarium stuff. Using a combination of local stores, clubs, and societies, and wonderful dealers online to purchase aquarium fish is always a good choice that will ultimately provide you with the best options for your setup. Feeding your fish — what types of food to buy Although you can buy canned fish food, nutrition goes beyond premanufactured dry food. Many species of fish have different nutritional requirements. A well-balanced diet for you fish can include prepackaged, frozen food, live food, and in some cases fresh vegetables. Taking care of sick fish Despite having the best setup possible, fish will eventually contract disease from time to time. This usually isn’t a cause for alarm because many fish illnesses can be cured. You need to be able to identify stress, spot common problems ahead of time to prevent disease, treat common illnesses, set up a hospital tank to treat disease, and understand the importance of a quarantine tank to avoid introducing sickness into your main tank with newly purchased fish. Never buy ill fish with the noble idea of taking them home and nursing them back to health. This practice will endanger your other fish and risk upsetting your current system.

Article / Updated 03-26-2016

Seeking a koi in top-notch health should be foremost in your mind, even ahead of color and pattern. This requirement becomes especially important if the fish must be shipped by air or ride in a vehicle for several hours to get it home. Such handling, even at its best, can quickly stress out a healthy koi for several days. If the fish is below par to begin with, the trip can be fatal. Of course, even generic koi should be free of malformations. Examining koi in a group Before you pick out a particular koi from a group in a quarantine tub or a dealer's show tank, look at them as a whole. Consider the following characteristics about the group: Are they oriented vertically in the water? Fish that are ill may list (tilt) from front to back or side to side. Unless they're feeding, the head shouldn't be oriented toward the bottom of the tank. Do they seem to move easily through the water with no jerkiness? Skeletal malformations, swim bladder problems, and a host of other conditions can disrupt normal swimming patterns. Are the fish rubbing themselves on the bottom of the tank or against objects within the tank? If so, they may be trying to dislodge parasites. Are the koi swimming about in a frenzied fashion, or do they seem unusually listless? Both behaviors can indicate water quality problems or disease. Are the koi gasping or gulping air at the surface of the water? This behavior can indicate low oxygen levels (which eventually stress the fish) or water quality problems. If the answers to the preceding questions raise any concerns, ask to see another batch. Better yet, resist your impulsive urge and find another source. However, if the koi pass the group test with flying colors, you're ready to take a closer look. Assessing a single koi Select the fish that interests you the most and ask to have it placed in a bowl. Take a few minutes to study it close up. Before you fall in love with its color or its pattern, get steely-eyed about its health. Expensive or not, buying an unhealthy fish makes no sense. As you give the koi a good inspection, ask yourself the following questions. If you answer "Yes" to any of them, move on to another fish, tank, or supplier. Does the fish have any rough spots? Do its scales seem to puff out away from the body? Koi whose scales stand out from their body like a bas-relief may be exhibiting pinecone scale, a symptom of an overall internal infection, or enteritis, which causes such pressure from within that the fish actually bloats, pushing the scales out. This symptom is a very bad sign. Is it missing part of a fin or part of its tail? Looking at the overall proportions of the fish, do you notice any stubby parts? Is its mouth asymmetrical or its snout sharply pointed? As the fish swims past you, is one side of the body wider or more curved than the other, rendering the fish asymmetrical in appearance? Does the tail curve up or wiggle to one side only? Are the eyes cloudy or protrude abnormally? You can also ask the dealer to bag the fish. When it's in the bag, you can examine the koi's mouth, underside, and tail. Signs of infection, such as fuzzy, grayish, or white patches, may appear on the lower aspects of the koi and aren't otherwise easy to see. Fish that look healthy may still carry external parasite eggs that won't hatch until conditions are right. Be aware that transferring the fish to a new pond may give these eggs the opening they need to proliferate, particularly if the fish has been in a cool pond and is moved to your warmer pond. This problem doesn't mean you bought an unhealthy fish or that the vendor's a crook. No treatment kills external parasite eggs.

Article / Updated 03-26-2016

Cotton wool or cotton ball disease is a charming name for Saprolegnia — a nasty fungus that grows when bad water quality stresses your koi. Expect to find it when the water contains quantities of uneaten food and when the pond has too many koi for its size. Fungus can attack any weakened portion of a koi, from the skin to the gills. It usually takes hold opportunistically, when the koi are stressed. Be sure that you always check for the presence of fungus when your fish suffer an unrelated trauma or illness. When a koi has cotton wool fungus, the fish develops what looks like a fine-textured fur coat over its body that's actually mold growing on the skin. Sometimes the fungus looks like a pale-orange or ivory-colored layer. As the disease progresses, the fungus grows longer, cotton-like tufts. Treat this disease by correcting the conditions that lead to the outbreak: Decrease the number of koi in the pond. Improve water quality via partial water changes; an upgraded filtration system; an ammonia remover like AmQuel Plus or Zeolite; and increased aeration. You can also use medication against the fungus. Adding methylene blue (a dye commonly used as a fish medication and available at most pet stores) to the pond at a rate of 1 teaspoon per 700 gallons helps kill the fungus, but individually treating each affected koi in a quarantine tub stops the progression of the disease much faster. Either sedate the koi or hold it so you can remove the patches of fungus with a cotton swab. Then dab the affected spots first with malachite green (a fungicide) and then with propolis (an antibiotic and topical treatment). Return the fish to the quarantine tub and watch closely to make certain no secondary fungal or bacterial infection sets in.