AQUATIC TURTLE CARE

Thomas H. Boyer, DVM

9888-F Carmel Mountain Road, San Diego, CA, 92129

(858) 484-3490

Introduction - Aquatic turtles are popular pets, but this does not mean they are easy to care for.In fact, they are among the most labor intensive of all reptiles to maintain.Inadequate care often results in problems for turtles.The following are some general guidelines for aquatic turtle care.Keep in mind that there are exceptions to most rules and there is no substitute for good information on the natural history.

Taxonomy - The most common genera seen in the pet trade in the United States include Trachemys (sliders), Chrysemys (painted turtles), Kinosternon and Sternotherus (mud and musk turtles), Graptemys (map turtles), Clemmys (wood and pond turtles), Apalone (formerly Trionyx, soft shell turtles), Pseudemys (river cooters), Chelydra (common snapping turtles), Malaclemys (diamondback terrapins), Macroclemys (alligator snapping turtles), Chelus (mata matas), Cuora (Asiatic box turtles), Chinemys (Reeve's turtle), Geoemyda (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, cement mixing tubs, stock watering tanks, and pond liners to elaborate outdoors 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 carapace size of all residents should not exceed 25% of the cage's floor surface area.Floor surface area does not include any inaccessible areas that the turtle cannot rest on.

Water Quality - Water laden with bacteria and nitrogenous wastes often stinks and can quickly infect turtle shell or kill turtles.Aquatic turtles should have little odor outside of feeding or unless associated with musk glands.Turtle odor suggests a major water quality problem.Clean water is crucial to good health; there are several means to assure this.

Frequent full water changes are one method of keeping water clean.One can keep the water cleaner by feeding in a separate container as most foods foul the water quickly.If the turtles are fed in their regular enclosure, the water should be changed within 12 hours of feeding messy foods.Initially some turtles may be reluctant to feed in the separate container but can be acclimated to this over time.Using the same water from the home container helps.

How often the water needs to be changed depends on stocking density.For instance, for three or less four-inch turtles, a 10-gallon aquarium should be changed two to three times per week and a 50-gallon aquarium once a week.Unless under gravel filtration is used, it is advantageous for full water changes to avoid any substrates.Sand or gravel make cleaning much more difficult.For smaller setups (10-gallon aquariums or less), one can carry the whole setup to a sink or bathtub for rinsing.Keep in mind that cleaning areas are a potential source of infectious bacteria, such as Salmonella.The 10-gallon storage container from Rubbermaid is easier to clean and more durable than a 10-gallon aquarium and is excellent for hatchlings.

For larger setups, one must drain the water.Portable electric submersible pumps can drain large volumes of water very quickly and make cleaning much less of a chore.These pumps are designed to drain swimming pools or flooded basements and are found in hardware departments of major department stores (such as Sears) or pool supply stores.The Little Giant Pump Company (Oklahoma City, OK) makes a very good one, the "Water Wizard," model 5-MSP, for about $65.00.Alternatively, one can use a siphon to drain the water, but this requires much more time.If one has the luxury of floor drains, one can install drains in the bottom of the cage, attach a hose, and drain the cage by gravity.Refill larger setups through a hose (with a nozzle) attached to a faucet.Separate drainage and refill hoses make cleaning much more convenient.When using a hose to drain or refill a cage is sure to carefully secure the end of the hose or inadvertent flooding will occur.

It is important to periodically 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.Thermometers facilitate this; with experience, one can gauge this with one's hand.Dechlorination of the water is generally not necessary; chlorinated water may help keep bacterial levels down.Obviously, with filtration systems, water must be de-chlorinated.Young turtles and those not accustomed to chlorinated water initially squint their eyes and have difficulty eating but quickly acclimate.

A partial alternative to the laborious task of full water changes is biological or chemical filtration.Filtration can decrease the time interval required for partial to full water changes but should eliminate them.The author’s initial impressions of fish filtration systems used with turtles was that filtration simply didn’t work.However, our knowledge and design of filtration systems for aquatic turtles has improved dramatically in the last few years.Filtration is now desirable whenever feasible, especially for larger setups.Keep in mind that turtles produce considerably more solid fecal and urinary waste than fish.Most retail aquarium supply stores sell filters designed for biological breakdown of fish waste, not turtle waste.Even if the water looks clean, it can still have a lot of nitrogenous waste in it.In general, select filters for turtles that are designed for large fish or dense stocking densities.As with all filtration systems good aeration of water (through air stones or water agitated from falling into the surface, such as with a waterfall) is important to support aerobic bacterial growth in biological filters.For small setups, internal submersible filters are gaining in popularity.The best filters for turtles are large biological or chemical filters, such as those designed for Koi, rapid sand filters and external canister filters.If the water level can be maintained within eight inches of the top of the tank, power lifting hanging filters is less expensive and simpler to maintain than canister filters but are much less effective due to lower flow rates and filtration surface area.Under-gravel filters need a deep gravel bed (7.5 cm or more), or the turtle may dig and expose the filter plate (Highfield, 1996).Once exposed, water will bypass most of the gravel as it follows the path of least resistance, and the benefits of biological filtration will be decreased.Foam rubber filters are essentially worthless.Disasters, such as die-offs, can result from poor water quality, particularly with low levels of oxygen saturation.For a more in depth discussion of water, quality and filtration see Highfield, 1996.

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 two tablespoons of aquarium salt and mineral mix per gallon of water.

Temperature - Water, and air, must be warm; 75 to 82°F are recommended for most species.Submersible aquarium heaters will keep the water warm while an incandescent 50- to 150-watt light bulb with reflector directed toward the basking area will create a hot spot for basking.Alternatively, one can keep the room temperature within this range.Some species such as mud and musk turtles, common snapping turtles (not alligator snapping turtles), and Chinese bigheaded turtles prefer it a little cooler.

Haul Out Area - 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.Platforms that are more elaborate can be built into the cage above water level with access via a plastic ramp or piece of wood.One also can use floating pieces of cork, hardwood driftwood, or plastic floating platforms.Snapping turtles and Matamatas do not need basking areas.

Nesting Areas - Nesting areas should be provided for adult females, even if adult males are not present.If a sufficient nest area is provided, dystocia may be avoided and oviposition stimulated.The Columbus Zoo, with their prodigious aquatic turtle breeding program, believes that temporarily rigging a nesting area or shifting a gravid female to a cage with a nesting area is far less successful than keeping a nesting area present year round.The nesting area should be approximately four to five times larger than the carapace of the female.Nest medium should be slightly moist sand or potting soil and two times deeper than the length of the carapace. 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 double as a basking area.

Ultraviolet light - Sunlight is by far the best source of UV light and should be provided whenever practical.Unfortunately, indoors, UV light is almost completely filtered by glass and plastic.Special UV transmissible glass and plastic are available but are generally expensive.There are several options besides natural sunlight.One is to provide preformed cholecalciferol in the diet.Vitamin D is fat soluble and thus stored for extended periods in the body.Unfortunately, vitamin D may be toxic when chronically overdosed and may lead to problems if there is excess calcium in the diet.

A wide variety of commercial reptile UV lights are available but it is important to evaluate each for specific UV-B output.As UV light intensity decreases exponentially with increasing distance, the lights should be within 24 inches of the basking turtles.Replace UV lights every 18 months as ultraviolet output decreases precipitously after this age.Plant lights, poster black lights (BLB lights), and incandescent lights do not produce UV light in the proper wavelength.

Feeding - Feed adults one to three times per week, hatchlings daily.Feed as much variety as possible.The majority of the diet should consist of whole animals such as mice, earthworms, slugs, snails, shrimp (with shells) and thawed frozen goldfish, guppies, trout, bait fish, and some smelt.Whole fish are better than gutted fish and can be fed chopped or whole.Most suppliers of feeder fish minimize their feeding to ensure good water quality in overcrowded setups.Ideally, fish should be well fed prior to being fed to turtles.Freezing for more than three days may eliminate transfer of some, but not all, parasites.Goldfish can be frozen 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 (fat inflammation and breakdown).Smelt can have high levels of thiaminase (especially after freezing), which can induce thiamin or vitamin B1 deficiency if fed exclusively.If fed in moderation, as part of a balanced diet, frozen fish should not cause any problems.

Most aquatic turtles will readily consume mice, from pinkies to chopped skinned adults.Older mice have more mineralized bone and are an outstanding source of bone for shell growth.Mouse liver is also a good source of vitamin A.A variety of insects (crickets, wax worms, mealworms, flies, moths, and grasshoppers) in moderation also are good.Be aware that insects are calcium deficient (see handout on Feeding Insectivorous Reptiles and Amphibians).Earthworms are widely available and nutritious; small turtles often need them chopped.Snails and slugs can also be fed.

Commercial diets can provide a smaller portion of the diet and should be soaked until soft before offering them to the turtle.A variety have been used including Trout, Catfish or Shrimp Chow (Ralston Purina), Hikari Cichlid Gold pelleted fish food (Kyorin Co., LTD), Reptomin Floating Food Sticks (Tetra), Tender Vittles or Happy Cat semi-moist cat foods (Ralston Purina), Gaines Burger semi-moist dog food (Gaines), and various commercial turtle diets.Patience and persistence is required with commercial diets because acceptance can take several weeks.heck the ingredients; desiccated insects are nutritionally inadequate and should not be fed.

Small amounts of lean raw beef, liver, gizzards, or chicken occasionally 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.

Many sliders and pond turtles become more herbivorous as they reach mature size and grow less rapidly.One can gradually increase dark leafy greens (kale, romaine lettuce, cabbage, watercress, endive, bok choy, escarole, spinach), duckweed, algae and fruits (apples, oranges, carrot, grapes, melons, bananas) for these species.

As much variety as is possible is recommended to ensure a healthy diet for aquatic turtles.If a balanced diet with whole mice is provided, multivitamin and mineral supplementation is not required and could be detrimental in the long run.Don not is discouraged if novel items are tasted and spit out initially; it can take weeks for turtles to accept new foods.

Neonatal Care - Hatchling aquatic turtles can be a challenge to raise.Avoid crowding neonate turtles.The Rubbermaid 10-gallon storage container works well for young turtles because it is easily cleaned and the nontransparent sides may offer additional security.Hatchlings may be shy and scramble for cover at your approach and can be reluctant to feed.Provide hatchlings with cover to retreat under such as floating pieces of cork, clay flower-pot pieces, plastic leaves (large enough that they cannot be ingested), or a small board or flat rock over two bricks.Be certain that cage props are stable so that they do not shift and trap young turtles underwater and drown them.

To coerce young turtles to feed, try small live insects such as two-week-old crickets, mealworms, wax worms, chopped pink mice, or small chopped earthworms.As the hatchlings begin to feed with more vigor, try a wider variety of foods.As soon as possible, try to get them eating finely chopped adult mice, guppies or small goldfish, all good sources of bone.Hikari Cichlid Gold pelleted fish food and trout chow are good because the pellets come in a wide variety of sizes that can be increased as the turtle grows.UV lights, proper temperature, and a wide variety of foods are important to prevent metabolic bone disease and ensure proper growth.

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

Predators - Predators, especially dogs, are fond of chewing on chelonians shells and appendages and can wreck havoc in a very short time.Small chelonians can be devoured without a trace.Raccoons and opossums will enter yards at night to prey on turtles.Other mammals and birds are also potential predators; small chelonians should always have screened outdoor cages to avoid mishap.

More Information – To get more information on aquatic turtles join the San Diego Turtle and Tortoise Society.See their web site (www.sdturtle.org) for a membership application and information on aquatic turtle care sheets. An excellent book on turtles is “A Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles” by A.C. Highland and published by Carapace Press.