Red eared sliders are semi-aquatic turtles. They make lovely pets, but there are a number of requirements and issues you must consider before buying one.
Size of tank:
1 inch length=10 gallons
Reds can live up to 40 years
Keep them in an aquarium or terrarium (an aquarium-like container with "land" as well as water). Although they spend most of their time in the water, they like to bask and a female who may lay eggs needs a proper place to do so.
These pets can be messy. Have a filter suited for aquariums three times the amount of water in your tank. Clean the tank regularly. Change the water.You should have a basking area ready for them like a log or a commercial made ramp.you will also need an uv light/fluorescent light to process vitamins and keep a hard shell + a regular light bulb 40 watt through 75 watt for basking purposes.
You could feed the turtles pellets. If you want to feed them something natural, that is fine. They are omnivores. Babies should have more protein, and adults need a lot of veggies. A multivitamin with calcium and vitamin D3 should be mixed two times a week. Do not feed them raw meat.
They can be carriers of Salmonella, and there are legal restrictions on their sale in the US. They come from the southern US, but are popular pets for other parts of the world, where they can become invasive species if released (or if they escape) into the wild.