AAAARGH... My A. polymnus that I've had for over two years has lost his marbles. He has been kept with a pair of false percs and a maroon clown for nearly a year and a half. About 4-5 months ago, the agression became to great, and he got his own "time out" tank. I drilled a 6 gallon Eclipse and have it gravity fed into the main tank. It is acting as a refugium as well, with several types of caulerpa. He has been fine, eating great, looking happy with his new pad, but now he's nuts! He is diving into the caulerpa and burying himself half in the sand. This is not a hosting behavior, that's for sure. It looks like he's trying to commit suicide! When he dives in, he just sits there for a long long time until I tap on the tank, then he goes spactic and runs into all of the corners of the tank and jumps out of the water (thankfully the lid is on). What the heck is going on??? I just did a water change over the weekend. This tank has been problem free (except agression, but that was solved months ago.) in fact, the tank and all of it's inhabitants have been moved from Wisconsin to here a little less than two years ago. Any help would be greatly appreciated! I'm off to check params, but the main tank looks great... is he just lonely???