A 30-gallon tank with a screen top or a Rubbermaid container 30 inches by 15 inches by eight inches is a good starter enclosure for small turtles. As your turtle reaches full size they will need at least a 70 gallon tank or a small pond (depending on the species). Plain glass on the bottom of the tank is the best substrate. For decoration, you can use a couple of larger rocks and plastic plants that are easy to clean. Avoid gravel or small rocks as it creates an environment with a lot of surface area to promote bacterial growth. Additionally, gravel is often ingested and can lead to intestinal blockage. Change the entire tank once every two weeks. It is important to perform partial water changes (approximately 50 percent of the tank volume) twice weekly to prevent buildup of waste. Use an underwater filter to help keep water clean between changes.
Most turtle species need to bask. Offer a sturdy area for your turtle to get its entire body out of the water, such as a stack of flat rocks or a small milk crate with a rock on it. A basking light should be used over the dry area. The basking area should reach a temperature of 85 to 90 F. You should also have a fluorescent 5.0 UVB bulb over the tank. Be sure there is not glass between the bulb and the turtle because the glass will filter the UVB. Both lights should be on ten to 12 hours daily. If you bring your turtle outside for natural sunlight (especially in warmer months) be sure to supervise them at all time to prevent injury or attack from predators.
Diet should consist of turtle pellets (such as Repcal) or turtle sticks. Also offer leafy greens such as Romaine lettuce, kale, collards, and red and green leaf lettuce (float them in the water and remove uneaten portions). You can also teach your turtle to eat in a separate container of water to keep the water cleaner.