Aquatic turtles are delightful popular pets. Unfortunately, their popularity doesn't mean they are easy to care for. Aquatic turtles require much more care than many people realize and are one of the most labor intensive of all reptiles to maintain. Veterinarians and owners are often unaware of how to care for this diverse group and inadequate care often results in health problems for captive turtles.

Common Species

Although it may seem beyond the scope of veterinary care, a rudimentary grasp of scientific names of common genera does much to enhance the veterinarian's image with reptile owners and more importantly, is essential for referencing further information. The most common genera seen in the pet trade in the United States arise from 3 geographic regions. Within regions they are listed by abundance in the pet trade. North American genera include Trachehemys (sliders), Chrysemys (painted turtles), Kinosternon and Sternotherus (mud and musk turtles, Graptemys (map turtles), Apalone (formerly Trionyx) soft shell turtles, Pseudemys (river cooters), Chelydra (common snapping turtles), Malaclemys (diamondback terrapins) and Macroclemys (alligator snapping turtles). Latin American genera include Chelus (matamata), and Phrynops (side necked turtles). Southeast Asian genera include Cuora (Asiatic box turtles), Chinemys (Reeve's turtles), Cyclemys (leaf turtles) and Platysternon (big headed turtles).

Housing

Housing requirements vary according to the size of the turtle and the number being kept. A variety of enclosures can be utilized from glass aquaria, plastic containers, stock watering tanks and pond liners to elaborate outdoor ponds. Outdoor enclosures should have some shade available. Never place an aquarium in direct sun, it could easily overheat. A rule of thumb for minimum cage size is that the combined surface area of all resident's carapaces should not exceed 25 percent of the cage's floor surface area. Floor surface area does not include any inaccessible areas that the turtle can not rest on. With the exception of large outdoor ponds, keep in mind one rule: the simpler the setup, the easier it is to clean. Avoid gravel or sand substrates because they make cleaning much more difficult. If more elaborate enclosures are set up with substrates, they should have filtration, bottom drainage and low stocking densities.

Water Quality

Clean water is crucial to good health and the best way to assure this is through frequent full water changes. Partial water changes are not acceptable. Several factors determine how often the water should be cleaned. Smaller volumes require more frequent water changes. For instance, for 3 or less - 4 inch turtles, a 10 gallon aquarium would need to be changed 2 to 3 times per week and a 50 gallon aquarium would need to be changed once a week. Thus, the larger the volume of water, the less frequently it needs to be changed. Obviously, stocking density will dramatically affect this. The more turtles in the cage, the more frequently the water must be changed even with very large volumes. Feeding frequency also affects water quality. The more often one feeds, the more often one cleans. Some foods foul the water quickly. If the turtles are fed in their enclosure, the water should be changed within 12 hours of feeding. The water can be kept cleaner by feeding in a separate container. Initially, some turtles are reluctant to feed in the separate container but can be acclimated to this over time.

When doing a full water change, it is important to scrub and rinse the cage well to remove residual bacterial growth on all sides. Abrupt changes in water temperature can kill turtles so make sure the water temperature after cleaning is similar to what it was prior to cleaning. Dechlorination of the water is not necessary, chlorinated water may help keep bacterial levels down. Young turtles and those not accustomed to chlorinated water squint their eyes a lot at first but quickly get over this. Water should be at least as deep as the width of the widest turtle's shell so that if overturned, the turtle will be able to right itself and avoid drowning. Diamond back terrapins live in brackish water and require addition of 2 tablespoons of aquarium salt and mineral mix per gallon of water.

Filtration can decrease the frequency of complete water changes but not eliminate them. Turtles produce considerably more solid fecal waste than fish. Most retail aquarium supply stores sell filters designed for biologic breakdown of fish waste not turtle waste. Keep in mind that even if the water looks clean, it can still have a lot of nitrogeneous waste in it.

Temperature and Light Requirements

As well as being clean, the water must be warm: 24 to 29°C (75 to 82°F) is recommended for most species. Some species such as mud and musk turtles, common snapping turtles (not alligator snapping turtles) and Chinese big headed turtles prefer it a little cooler. If air temperatures drop below 24°C (75°F), water temperatures are going to be well below 21°C (70°F). While many species can exist at lower temperatures, they prefer and will do better at warmer temperatures. Therefore, submersible aquarium heaters are needed. Use a liquid crystal display thermometer outside the tank to monitor temperature. Glass thermometers are not recommended because turtles may ingest them.

A dry, "haul out" area should be present so that turtles can crawl out of the water, dry off and bask. Basking is a means of behavioral thermoregulation whereby turtles can achieve their preferred optimum body temperature. Basking areas can be as simple as a flat rock resting on submerged bricks, or a cinder block. More elaborate platforms can be built into the cage above water level with access via a plastic ramp or piece of wood. One can also use floating pieces of cork, hardwood driftwood, or plastic floating platforms. The basking area should be large enough for all turtles to completely emerge from the water and secure enough that it won't topple and trap a turtle under water. Some species are agile climbers so be sure to include a screen top to prevent escape. Snapping turtles and mata matas don't need basking areas.

Nesting Areas

Nesting areas should be provided if adult female turtles are kept. Even if conspecific males are not present females may still lay eggs which may or may not be viable. If a sufficient nest area is provided, dystocia may be avoided and oviposition stimulated.

The nesting area should be approximately 4 to 5 times larger than the carapace of the female. Nest medium should be slightly moist sand or potting soil and 2 times deeper than the length of the carapace. The nest area should have easy access for turtles. Nest area containers can be made from a large plastic trash can cut in half or a variety of smaller plastic containers. The nesting area can also serve as the basking area.

Diet and Nutrition

A balanced diet is very important for good health. A wide variety of foods should be fed. Fish (goldfish, guppies, trout, bait minnows, smelt) are all suitable. Whole fish are better than gutted fish, and can be fed chopped or whole. Most suppliers of feeder fish minimize their feeding to insure good water quality in overcrowded setups. Ideally, fish should be well fed prior to being fed to turtles. Freezing for more than 3 days may eliminate transfer of parasites. Goldfish can be frozen in water in ice cube trays to reduce freezer burn. Wild caught sticklebacks and mosquito fish should not be fed because they are natural vectors for several serious parasites. Avoid large quantities of oil laden species such as mackerel, and to a lesser extent smelt and goldfish that are known to induce steatitis.

Fish should not make up the majority of aquatic turtles diet except for the mata matas which are fish specialists. Mata matas can be trained to eat whole skinned mice.

Chopped or whole baby mice , or chopped, whole, skinned adult mice are eaten readily by many species. Baby mice (pinkies) have a calcium to phosphorus ratio less than one for the first week of life and can reduce metabolic bone disease if fed exclusively. Older mice have more mineralized bone and are an outstanding source of bone for shell growth. Chopped, whole, skinned, adult mice are one item that can and should be fed in large quantities.

Commercial diets such as floating food sticks, tender vittles cat food, gaines burger semi-moist dog food are all fine in moderation. Commercial diets should be soaked until soft before offering them to the turtle. Patience and persistence is required with commercial diets because acceptance can take several weeks. Desiccated insects are nutritionally inadequate and should not be fed.

A variety of insects such as crickets, waxworms, mealworms, flies, moths, etc. in moderation are also good but keep in mind that insects are calcium deficient.

Earthworms are widely available and nutritious, small turtles often need them chopped. Lean raw beef, liver, or chicken can be fed but are severely calcium deficient unless bone is present. Hamburger is not recommended because it is calcium deficient and the high fat content will leave a greasy film on the surface of the water. Crayfish can injure turtles and can transmit Beneckia chitonvora, a shell eating bacteria and should not be fed.

Common Health Problems

The most common problems seen with aquatic turtles are the result of poor husbandry. It is beyond the scope of this article to review diseases of aquatic turtles, but a few are presented to illustrate the importance of good husbandry.

Skin infections and shell abscesses are usually due to poor water quality and no dry haul out area. Often this occurs in the pet trade as a direct result of overcrowding and unsanitary conditions. Shell abscesses manifest as soft, fluid-filled, whitish or yellowish areas under the keratin layer of the shell which bleed easily. The underlying bone is usually infected and truly severe infections can penetrate the coelem. Most cases respond well to gentle, but thorough debridement of all infected keratin and bone and daily scrubbing with chlorhexidine scrub (Nolvasan wound cleanser, Fort Dodge). Water should be changed daily during treatment. Systemic antibiotics are usually not necessary unless bone is heavily involved. Permanent scarring of the shell results.

Pneumonia can result from cool environmental temperatures, poor water quality and vitamin A deficiency (as well as many other causes). As the affected lung fills with material, it becomes heavier and the turtle floats unevenly. Open mouthed breathing with a click or squeak is often present. Culture and sensitivities and cytology of tracheal washes can guide therapy yet it is perhaps much more important to correct environmental conditions.

Several common problems are associated with inadequate nutrition. Vitamin A deficiencies and eye infections can cause blepharitis similar to that seen in box turtles and the treatment is similar.

Metabolic bone disease, evidenced by stunted growth and a soft deformed shell with upturned marginals and ventral deviation of the central carapace, is most common in young growing turtles. The sale of turtles less than 4 inches in carapace length is now prohibited in the United States so metabolic bone disease is not as common as it once was. Aquatic turtles shells should be unyielding and feel like solid bone (with the exception of soft shell turtles).

Parasites are prevalent and fecal examinations should be stressed to owners. Dogs like to chew on aquatic turtles as much as box turtles, treatment is similar. This can be prevented by securing the cage with a screen top. Children should be supervised when handling turtles to prevent injury to either party. A fall of several feet can result in serious shell fractures.

Some turtle species, such as snapping turtles, large soft shell turtles, mud and musk turtles and big headed turtles are aggressive towards other turtles. These species can cause severe lacerations and should only be kept with others of the same species and size. In addition many aquatic turtles can be asymptomatic carriers of Entamoeba which can cause serious gastrointestinal disease in other reptiles.