Do all red eared sliders live in water?

Yes, red eared sliders are strictly aquatic reptiles. This means that they spend the majority of their lives in water, but they do require to be able to come out onto land whenever they feel the need to. They need to come onto land in order to dry out their shell and skin, this will help reduce the risk of fungus and parasite infection. Also, their eggs are lain on land and they may grab at a couple of bugs for a snack. So although they do mainly live in water, land is still a necessity.