Red eared slider turtles are semi-aquatic and spend a significant amount of time basking so they need a tank that is large enough to provide both water for swimming and an area where they can dry off and bask. When cared for properly, red eared sliders can live a long time and be very entertaining pets but the set up of their tank is vital to them having a good quality of life.
Red Eared Slider Turtle Tank Size
You should plan on having 10 gallons of water per inch of turtle as a general rule of thumb but a 20 gallon tank is a minimum size for hatchling red eared sliders.
Keeping in mind that red eared sliders can read 10-12 inches as adults, you can see that eventually you will need a very large tank. Large plastic containers or storage tubs are good alternatives to aquariums as long as you don't mind not being able to view the turtles from the side. As long as the container is tall enough and the basking area is positioned so that the turtles can't climb out of it you won't need a lid.
Red Eared Slider Turtle Tank Water
Red eared sliders need an adequate amount of water in which to swim. At a minimum, the water should be at least 1.5 to 2 times as deep as your turtle is long (so a 4 inch turtle should have a minimum depth of 6 inches). The length of the water area should be at least 5 times the length of the turtle, and the width should be at least 3 times the length of the turtle. As long as your turtle can get out of the water and there is no place your turtle can get trapped underwater, you do not need to worry about your turtle drowning as they are strong swimmers.
Between feeding and defecating, turtles are pretty messy creatures so your turtle tank should include a good filtration system such as a power filter or canister filter to keep the water clean. Choose a filter rated for at lease double the amount of water you will be filtering since turtles are such messy pets.
Filtration will reduce the frequency of water changes but your turtles will still require 25% water changes weekly and a thorough cleaning once a month or more. Feeding your turtle in a separate container helps minimize the mess in their tank and reduces the load on the filtration system.
Red Eared Slider Turtle Tank Basking Area
The basking area for your turtle can be provided by stacking smooth rocks, sloping smooth, large gravel to one side to make a land area, using wood, or a plastic "turtle dock." Whatever you choose to construct a basking spot, make sure your turtle can climb onto it easily and that it allows your turtle to completely dry off.
Red Eared Slider Turtle Tank Decorations
When designing a tank, keep it easy to clean (i.e. uncluttered) and remember that turtles may knock things over and push stuff around. Plants may be a nice touch but turtles are likely to make a snack of them or uproot them (plastic plants will likely be uprooted and just make cleaning more difficult). Likewise, gravel can be a nice touch but it can also make the tank harder to clean and you must make sure it is large enough that it won't be accidentally swallowed.
Red Eared Slider Turtle Tank Heat
The water in a red eared slider turtle tank should be kept at 75-78 degrees Fahrenheit (23-26 degrees Celsius), and 78-80 degrees Fahrenheit (26-27 degrees Celsius) for hatchlings.
The ambient air in the tank should be around 75-80 degrees Fahrenheit (24-27 degrees Celsius), with a basking spot at 90-95 degrees Fahrenheit (32-35 degrees Celsius).
A submersible water heater can be used to keep the water warm if necessary but a broken heater is a potentially lethal situation if it heats the water up too much. You can protect the heater so the turtles can't bump it by placing it behind something (e.g. bricks) or by fashioning some sort of cover such as a piece of PVC pipe. You can also get durable plastic heaters such as the Visitherm Stealth heater. Get a good aquarium thermometer (not a stick on strip) and monitor the water temperature.
A basking spot light should also be provided over the area where the turtle can get out of the water to keep them warm. A reptile bulb/heat lamp in a reflective lamp can serve this purpose but make sure there is no way the turtle can touch the light or that the light can fall into the water.
The basking light will help heat the air in the tank as well.
Red Eared Slider Turtle Tank Light
In addition to the basking light for heat, a full spectrum reptile UVA/UVB light should be provided. Exposure to UVA/UVB is necessary for proper calcium metabolism and also appears to have other benefits to overall health such as improving appetite. It is also nice to take your turtle out into natural sunlight in warmer weather if you can. Get a proper reptile UVA/UVB bulb and follow the manufacturer's guide regarding placement of the bulb (UV rays diminish the farther away you get from the bulb so placing the bulb in such a way that the turtle can benefit from the UV is important). It is also important to replace the bulb as recommended by the manufacturer, since the intensity of UV produced diminishes over time. If your turtle lives outside this light is not necessary.
Edited by Adrienne Kruzer, RVT