Housing Aquatic Turtles

By Laurie Hess, DVM; Rick Axelson, DVM

For the purpose of this discussion, the common and popular red-eared slider will be used as a representative for a pet aquatic turtle to describe proper housing for aquatic turtles.

An improper environment is one of the most common causes of health problems encountered in reptiles next to improper nutrition. Properly housed and fed turtles grow rapidly and are healthier and happier.

What type of cage does my red-eared slider require?

Aquatic turtles should be kept in as large an aquarium as possible. As your turtle grows, so does the need for a larger enclosure. Therefore, it is better to start juvenile, growing turtles in as large a tank as possible right from the start. The aquarium environment should have enough water for the turtle to swim, a dry area on which the turtle can escape the water to bask, a heat source, and a source of ultraviolet (UV) light.

Aquatic turtles require enough water to allow them to swim fully submerged. Some minimum guidelines suggest the depth of the water should be at least 1.5-2 times the shell length of the turtle, and the length of the swimming area should be 4-6 times the shell length. Another suggested minimum is 10 gallons of water per inch of shell length, plus 15-25% of the surface area for a basking or dry zone. A dry landing place should be large enough to allow the turtle to climb completely out of the water; either a large rock or a secure stack of smaller rocks (with a flatter top on which to easily sit) works well. The landing place should be easily accessible to the turtle and should be at the same end of the tank as the basking lamp. A standard submersible fish tank heater should be used to heat the water to a temperature of 75-82ºF (24-29ºC). An aquatic thermometer can be used to regularly monitor water temperature changes.

"Clean water is crucial to optimal health."

Clean water is crucial to optimal turtle health. Since pet turtles eat and eliminate in the same water, the tank water must be changed at least once weekly or more frequently if it becomes dirty. To maintain a relatively constant, normal bacterial flora in the water, many turtle owners will change 50% of the water every week; on the third or fourth week, they empty the entire aquarium and clean it thoroughly. Other people do not recommend partial water changes but empty all the water at once to change it. Regardless of how water changes are performed, ensure the water temperature is correct before reintroducing the turtle to a newly cleaned tank, as abrupt water temperature changes can affect the turtle’s immune system function and ability to digest food, ultimately leading to disease. A good quality water filter can be used to help keep the water clean in between changes. Some of the better, more powerful filters pump the water out of the tank, process it and return it to the tank. Feeding your red-eared slider in a separate "feeding tank" also will help reduce food debris from building up in the turtle’s main aquarium.

What else do I need in the aquarium?

Turtles are ectothermic, meaning their body temperature is regulated by their environmental temperature. Environmental temperature can affect the red-eared slider’s activity level, as well as their immune system function and ability to digest food. They slow down in cooler temperatures and tend to be more active when it is warmer. A heat source is necessary for all reptiles to maintain their environmental temperature within a constant range. In addition to regulating the water temperature (described above), you must monitor the temperature of the basking area as well.

A focal heat source may be provided using a 100-watt incandescent bulb with a reflector hood or other type of commercially available heat lamp or ceramic heating bulb. The heat source should be placed outside and above one end of the aquarium, over the dry basking area, such that there is no direct contact between the heater and the water or the turtle, therefore avoiding any risk of accidental burning. The basking area temperature, monitored daily with a thermometer, should be 75-88ºF (24-31ºC). The goal is to provide a hot basking area and a cooler area, far away from the basking area, to establish a temperature gradient such that the turtle can regulate its body temperature by moving through the gradient. At night, when the turtle is sleeping, lights should be turned off, and extra heat may not be required, as long as the temperature does not fall below 65-70°F (18-24°C). Sustained lower temperatures may cause the turtle to stop eating and will

"Plastic plants can be dangerous if the turtle attempts to eat them."

Plants can be used for decoration as long as they are safe for the turtle to eat. Plastic plants can be dangerous if the turtle attempts to eat them. Speak to a knowledgeable pet store employee or veterinarian about safe plants; if you are not sure that a plant is safe, do not use it in your turtle’s tank. Stones may line the bottom of the aquarium, but they must be smooth and too big to be eaten; turtles that eat stones can suffer from serious intestinal inflammation and/or blockage. Avoid sand or gravel as this particulate matter is commonly ingested by turtles leading to gastrointestinal tract obstruction. If stones are used in the tank, they must be washed and cleaned frequently, as they accumulate algae, fecal material, and food debris, making them unsanitary over time.

Does my turtle need UV light?

A wild reptile may spend many hours a day basking in the sun, absorbing UV light. These wavelengths of light are essential for the body to manufacture the vitamin D3 it needs for proper calcium absorption from food in the intestines. Vitamin D3 is manufactured in the skin. Failure to provide UV light can predispose your pet to nutritional metabolic bone disease, a  common condition of pet reptiles in which they fail to absorb calcium from food and instead extract it from their own bones, making the bones weak and susceptible to fracture. This condition is fatal if not recognized and treated. A UV light source should emit light in the UV-B range (290-320 nanometers) to prevent this condition. Most bulbs sold commercially for use with reptiles provide both UV-A and UV-B, but it is the UV-B part of the light spectrum that it critical to promoting proper calcium and phosphorus balance in a reptile’s body. The UV output of these lights decreases with age, so they should be replaced every six months or as directed by the manufacturer.

For UV light to be effective, it must reach the pet in an unfiltered form, with no glass or plastic between the pet and the light, and the light source should be within 12-18 inches (30-45 centimeters) away from the turtle for it to receive maximum benefit. Regular exposure to natural direct sunlight outside (unfiltered through glass) is encouraged and recommended whenever possible in warmer climates. When pet turtles are outdoors, they must be provided with a shaded area for it to escape the sun if it chooses. Always supervise your pet turtle if you take it outside to bask in the sun, both to prevent escape and to prevent attack from other animals roaming in the neighborhood.

"The UV output of these lights decreases with age, so they should be replaced every six months or as directed by the manufacturer."

Consult a veterinarian familiar with reptiles if you have any questions or concerns regarding proper lighting or housing for your red-eared slider, and of course, thoroughly wash your hands after feeding, cleaning or handling turtles, as they can carry and transmit Salmonella bacteria.

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