Discovered this a couple weeks ago and been monitoring it. It was initially in the crevice of another rock for a few days, but moved to this area a few weeks ago and has been here ever since. Seems to be active during the day, and hides at night. The "arms" move away when touched by another tank inhabitant, but don't retract. Otherwise they just seem to stretch out and "search" in the flow and along the rocks surface.
When it first moved into its current position under the rock, the shell was the other way around, and all the "arm strings" seemed to be coming out the shell. I don't know cause somehow the shell is now the other way around (hermits are constantly walking over it so it was most likely them).
When it first moved into its current position under the rock, the shell was the other way around, and all the "arm strings" seemed to be coming out the shell. I don't know cause somehow the shell is now the other way around (hermits are constantly walking over it so it was most likely them).