Nerite Behaviour

[Trout]

I have a tiger nerite and it is cruising around on one rock in my aquarium. It's a red glass heart-shaped piece, and he's been roving around on that 1-inch space almost all day. At least he's not all curled up partially in and out of his shell. I moved him because I think something about the pimafix and melafix made him uncomfortable in his old home. Weird, right? Anybody else have any experience with this strange behaviour?

[Trout]

Update:
He is no longer sticking to the same rock. He's moved around the tank a bit, but now I believe he's sleeping at the edge of the water.