I've had a GBTA for about a month now and he has stayed on the same rock this whole time, although he did move to different sides of the rock. Last night I started to get ready for a water change by taking a powerhead a blasting the rocks and barebottom to get the detritus out. This morning I noticed my nem on the bottom of the tank, off his rock which I thought he couldn't get off of. His tentacles are stringy and he doesn't look happy. I'm planning on doing the water change either tonight or tommorrow with RO/DI of course. Should I be concerned???