Ive had a RBTA for about 4 months. I placed him on a rock ledge when I first introduced him to the aquarium. The RBTA liked it there and backed up to the rock behind it and wedged itself in. It never moved from there. I feed it once sometimes twice a week with mysis. All parameters are in check. ph 8.3 amonia 0 nitrite 0 nitrate 0 phos 0 calc 380 alk 8 current temp 80 and varies between 80-82 daily. I have a 125 display with a large sump/fuge with triple metal halides. I know these guys are prone to move but even after they have been in place for a long period of time? I noticed him hanging off the bottom of the rock he was originally placed on just before lights out. Not deflated, has good coloration, and ate less than a week ago. Whats the problem here?