right now it's in the 40 gal QT with no substrate and just a flower pot. The salt is 1.019 ppm the ammonia nitrite nitrate are all 0 he seems to be eating less and less now, but he hasn't stopped. I heard that they eat seaweed but he wont touch it. Aside from the frozen angel formula, I've mainly been feeding him the same stuff that the other fish eat; a mix of spirulina flakes, some formula 1 and 2, several different pellets. He likes it as long as it is on the bottom of the tank. He will be moving into a 120 gal tank (in three weeks hopefully) with a very aggresive YT, three oblivious heni, three mildly aggresive tomato clowns, and one non-aggresive neon pseudochromis. When I explain to people that I have live rock in my tank they always seem to think that means I have decorative coral, which I don't. I only have about ten lbs of live rock (a friend of mine wanted to know if I wanted it so I said why not) which may not actually be alive, but it still makes more caves. Presently I have good amount of hiding places but I would like to put a lot more rocks in because the heniochis cannot find a place for themselves that they seem to enjoy. My fish are all quite small still and I heard that the Imperator was increadibly aggresive so I found one that was a little smaller than most of the fish in my tank. He will also be the last fish I add. I hope he lives long because he's already my favorite.