Yesterday, I had placed some rocks that are all about 3cm or more in width at the bottom of my turtles tank for decoration and make their tank more lively.
I woke up today and noticed that my turtle keeps biting a certain rock. He's not chipping it, and the rock is almost twice the size that he is.
Should I be concerned with this behavior and take out the stones? Or is he just playing with his new habitat?

