They just like to cover up the water so no one "finds" it... *eye roll*

But yes, I've kept them separated before and they do just fine. The male will start to stink ALOT faster though, IMO, being alone. If you can, get about 5-6 more females and just stick them all, plus the male, in a 10-gallon and let them have at it. The aggression will be more evenly distributed and no one should get picked on more than anyone else(or we'd hope).