The last couple days, I've noticed Ralph doing something strange. In his tank, there's some river rocks (about a dozen), they've been in there at least 2 months, and there is one black one about the size of my fist. Ralph is about 7 inches, so he's about twice as big as this rock. Usually, he just pushes around the rocks, or "digs" in them. But recently, the one black rock went under his "cave" area.
For the last two days, he's been sitting on the bottom, staring at it, sometimes digging at it so it spins around, and I think he even tried to bite it. Should I take out the rock so he doesn't end up hurting himself? Or should I just move it so it's not under his hiding place? Or should I just leave it in because he seems to be entertained by it?
There's other rocks the same size of different colours, but he's never bothered them.
Also, since he's been so interested in this rock, I haven't seen him basking (water and basking temp are the same as always).


