I have two yellow-bellied sliders (Trachemys scripta scripta). The water is more than 6cm tall, the aquarium is 50cm x 30cm and the turtles are like 7cm long. The aquarium is indoor. They have semi-direct sunlight (there's the window in the middle), a heater, and two gadgets:
- one bridge, which grants them shadow and also they can walk over to have dry ground;
- a rocky mountain - actually I think it should be bigger - in which a turtle fits perfectly.
I read that turtles need a dry space and sunlight, but most of the time I see them under the bridge. They don't struggle for the space at all. If I move them manually to the dry mountain or above the bridge, they immediately fall back below the bridge.
Under what conditions is it normal that they want to reject staying on the illuminated and dry grounds the whole time? Is it somehow a sign of sickness?