I have had a BTA on the same rock for more than year. It split into 2 a few months after I got it. A third one showed up a few months ago and was living on the same rock, high up under the lights, with the other two since then. Yesterday I discovered it 3 ft away over on the other side of the tank hiding under a torch coral. Any ideas on why it would move so far? If it wanted to get out of the light it could have just moved a few inches?