I had one in a 38 tall for many years. He'd nod his head and do silly dances when I looked in, very friendly, happy and healthy. OK, you wont believe this but he was jealous of the TV. When I'd watch TV and not him, sometimes he would go into shock colors, curl up a little and float to the bottom of the tank and lay there untill I'd come look at him. Not many tank mates though. Just LR from every ocean and my "unsuitably delicate for the public species" rescue mission of the month. Oh, and a Fire Goby and a Royal Gramma.