Housing
Red-eared sliders are semi-aquatic, so the habitat should provide an ample water area. Fishbowls and 10-gallon aquariums are not adequate; the minimum container for one turtle is a long, 30-gallon tank.
There should be easy access to a dry area for basking. You can use a piece of driftwood or a floating ramp designed for aquatic turtles.
Equip the aquarium with a good filtration system and maintain it regularly. You should empty the aquarium and thoroughly clean and disinfect it using a bleach/water solution once a month.
TEMPERATURES
The water temperatures should be between 70 and 80 degrees F; air temperatures should range from 70 to 80 degrees F; and the basking spot temps should reach 85 to 90 degrees F.
You can accomplish these temperatures by using an incandescent reptile light and a water heater placed in an area of water the turtle can't reach.
FULL SPECTRUM LIGHTING
Full Spectrum Lighting should be provided 9 or 10 hours every day. The fixture has to be placed within 12 inces of the animal and the light must not be filtered (through glass or mesh). The bulbs used should emit both UVB and UVA waves.
On warm, sunny days you can take your turtle outside for natural sunlight.
DIET
Young red-eared sliders are primarily carnivorous and become vegetarians as they get older. Commercial turtle food, feeder goldfish, crickets, earthworms, greens and fruit can and should be offered. These turtles will eat only when in water.
HEALTH
Watch your turtle for any signs of illness: cloudy, closed or swollen eyes; swollen cheeks; open mouth breathing; bubbly mucous around the nose or mouth; runny stools; loss of appetite; listlessness; spots appearing on plastron (bottom shell), carapace or body; soft shell or excessive shedding. Significant changes mean it's time for a visit to the vet.
NOTES:
If maintained at the proper temperatures, fed a healthy varied diet and kept in a stress-free active environment, your turtle may outlive you: some individuals have lived more than 100 years.
RECOMMENDED READING
Melissa Kaplan's RES Information http://www.anapsid.org/reslider.html