In the wild, aquatic and semi-aquatic turtles live wherever there is a constant source of water, coming out to forage, bask in the sun, or lay eggs. Quick-running rivers, slow, meandering streams, and tiny creeks all support turtles. Swamps, ponds, lakes, and even brackish (salty) marshes have chelonian residents.
Aquatic turtles rarely enjoy being handled; in fact, most have a well-developed flight instinct. For these turtles, anything that moves is a potential predator, and they view your hand reaching into the aquarium as a predator attacking. Therefore, aquatic turtles should be viewed as decorative pets, much like tropical fish.
Aquatic and semi-aquatic turtles are relatively intelligent and remarkably adaptive, able to cope with many changes in their environment. Habitat loss, however, is something that these remarkable turtles can't deal with. As a result, turtles are becoming quite rare in some areas.
In captivity, however, several species of aquatic and semi-aquatic turtles make interesting and rewarding pets.
A closer look at species
Red-eared sliders (Trachemys scripta elegans) are colorful, hardy, long-lived turtles. The wood turtle (Clemmys insculpta), although not as colorful or striking as the red-eared slider, is, in turtle terms, intelligent and fairly easy to care for. The painted turtle (Chrysemys picta) is an attractive North American turtle that likes to bask in the sun or under a heat lamp. The matamata (Chelus fimbriatus) is an odd-looking side-necked aquatic turtle. This turtle's head looks like a leaf. When startled, instead of pulling its head into its shell, its neck folds sideways, hence the description side-necked turtle.
Some aquatic turtles should be kept only by careful, experienced keepers. The various soft-shelled turtles are very different in appearance; instead of a hard, bony shell, these turtles have a leathery shell. This different look attracts many potential owners, but beware! Some soft-shelled turtles, like the Florida softshell (Trionyx ferox), are known for their aggressive nature. These carnivorous turtles bite anything that moves in their tank, including the hands or fingers of their keepers!
Most aquatic and semi-aquatic turtles are carnivorous (meat eaters) or omnivorous (eating whatever is available, meat or plants), although not all are as aggressive as the soft-shelled turtles. Most of these turtles eagerly catch and eat fish, scavenge, and eat berries, ripe fruits, and some water plants. As pets, these turtles need fish to catch, commercial turtle food, occasional canned meat, and some berries or fruits. Some species have very particular nutritional needs.
Some aquatic turtles aren't good pets. Common snapping turtles (Chelydra serpentina), alligator snapping turtles (Macroclemys temmincki), and big-headed turtles (Platysternon megacephalus) are all unsuitable pets because they bite — and bite hard! The big-headed turtle is also quite an escape artist and an accomplished climber. And alligator snapping turtles can get quite large, making it difficult for even experienced keepers to maintain a clean environment.
Considering aquariums
Aquatic and semi-aquatic turtles need an aquarium (or other waterproof enclosure) that provides plenty of room for swimming as well as room for the turtle to climb out of the water, dry off, and bask under a heat lamp. One or two small turtles could live in a 20-gallon aquarium sectioned off to provide both environments (water and land). Figure, as a general rule, an 8-inch aquatic or semi-aquatic turtle needs at the smallest a 20-gallon (low and long rather than tall) aquarium. Each added turtle should have an additional 10 gallons. So if you have three 8-inch turtles, the smallest the tank should be is 40 gallons. Most adult turtles eventually need a bigger tank than 20 gallons. Before getting a turtle, prepare for this eventuality.
Aquatic turtles rarely enjoy being handled; in fact, most have a well-developed flight instinct. For these turtles, anything that moves is a potential predator, and they view your hand reaching into the aquarium as a predator attacking. Therefore, aquatic turtles should be viewed as decorative pets, much like tropical fish.
Filtration systems
Aquatic turtles defecate in their swimming water. Because they are carnivores, the water gets dirty quickly. To keep the aquarium clean, keep smells to a minimum, and prevent disease, the water portion of the enclosure or aquarium must be circulated and filtered unless you're prepared to change the water daily. Because few people have that kind of time, a heavy-duty filtration system is a good investment.
After you set up the aquarium or enclosure, aquatic turtles don't require a great deal of your time until it's time to clean the aquarium. This may happen every two, three, or four weeks, depending on the size of the tank, how many turtles you have, the size of the turtles, and the efficiency of the filtration system.
A filtration system can be expensive. Tell the salesperson what you will be using the system for and how much water (in gallons) you anticipate filtering, and then get the best system you can afford. A cheaper filtration system requires you to clean and change the water more often.
Enclosures
Setting up an aquatic turtle tank can be somewhat costly, depending on the size of tank you choose. A simple glass aquarium — 20 to 30 gallons in size — runs from $60 to $100, depending on the brand name and whether it has a cover and a light. Because you need a cover and a light, go ahead and get them all when you buy the aquarium. Then you know that they'll fit.
For semi-aquatic turtles, most major pet stores carry a kit that enables you to divide the aquarium into two sections: part for water and part for land.
As is true with many reptiles, the turtles will probably be much less expensive than their enclosure. You can usually purchase a red-eared slider for $10 to $30, depending on the size of the turtle. The rarer a species of turtle, the more expensive it is.