Light: If possible, provide exposure to direct sunlight, but guarantee the temperature within the cage will not become too high. NEVER place a glass or acrylic aquarium in direct sun, as it may become too warm. If the outside temperature is within the turtle's comfort zone, it could be placed in an outside tub. Be sure it can not escape and that it is safe from small children and predators.
Full spectrum ultraviolet (UVA and UVB) fluorescent lighting should be used to enhance the turtle's production of Vitamin D-3, and provide it with a more natural habitat. Bulbs must be replaced after 6 months, as their ability to emit true full-spectrum light diminishes over time. The light source should be within 18-24 inches of the turtle. The light should shine directly on the turtle, and not be filtered through glass or plastic. It should be on a timer so the turtle has a normal day-night cycle.
Water: Red-eared Sliders need a water temperature of 75-86°F. Remember, they are cold-blooded animals and their metabolism will slow and they will become inactive if the temperature is too cold. This can also have an adverse effect on their digestive systems and result in severe health problems. Water temperature can be maintained through the use of a submersible aquarium heater, which is on a thermostat. In general, estimate that you will need 5 watts per gallon of water. Be sure the thermometer is below the water line, and turn it off when removing water from the aquarium. Follow the manufacturer's directions to prevent the risk of electrocution. An accurate thermometer should be immersed in the water so the temperature can be monitored daily.
Water quality is critical to the health of the turtle. Because uneaten food items, urine, and feces can contaminate the water, it becomes a very suitable place for bacteria and other organisms to grow. This is unhealthy for your turtle, and not very aesthetic for you, since the aquarium will smell. The aquarium will need to be cleaned, and the water removed and replaced on a regular basis. Be sure, when changing the water, to have it at the right temperature before placing your turtle back in the aquarium. In addition, a dechlorinating agent should be used to treat the water prior to adding it to the aquarium.
How often the water needs to be changed depends, to a large part, on whether the turtle is fed in the aquarium or moved to a separate feeding tank, and if there is a filtration system in the tank. If moved for feeding, the water will generally need changing weekly. To accomplish this, a siphon is used to remove a portion, usually 25-50%, of the water. The siphon can be used like a vacuum cleaner, to remove debris from the bottom while it is siphoning water. Every 1-2 months, depending upon the conditions, the entire aquarium should be drained, cleaned, and refilled. Never start a siphon with your mouth.
There are a variety of aquarium filters which can be used to remove some of the debris and chemical buildup from the water in the aquarium. Depending upon the design and size of your aquarium and turtle, an external canister, internal canister, or an undergravel filter are most commonly used. External filters allow more room for your turtle inside the aquarium. As with the size of aquarium, the bigger the better; never skimp. The use of an air stone may help to move water and improve filtration.
Adding aquatic plants can assist in removing wastes from the water, but also may be eaten by the turtle, and thus produce more waste. You may have to experiment with your own turtle, to see if plants aid or hinder the maintenance of water quality.
Heaters, lighting, and filters should be plugged into a ground-fault interrupter, which will reduce the risk of electrocution if the equipment malfunctions, or if it is nonsubmersible and becomes wet. To avoid the possibility of water running down the power cord into the receptacle, either have the interrupter higher than the aquarium, or form a drip loop so that part of the cord is below the receptacle on the interrupter.
