I have a single in one of my nanocubes and it is always out in the open near its favorite coral. I also have a nanocube that has a fairly large group of these neat little guys, the only other tankmate (other than a couple of snails) is an anenome shrimp. I think that the group has a bit more dancing and showing for each other than the single sexy but it seems to be fine by itself. HTH, Skip