mine do that toooo! They can't stand to be near each other (or away from each other)...always playing, bickering and chasing but as soon as one swims away they all follow him and hang out in a group again ,I can't figure them out ,but they're so interesting to watch I don't think I'll add any other top dweller's...I'll just leave it fronts only (ooooh,now if I could get my hands on some more this size )freshmike said:the fronts have been very playful....they don't like each other....LOL!!!