Originally Posted by fryup
i would recomend taking that 1 platy back to the store...
also i had 2 males and in the morning as soon as i turned the light on they would have a "stand off" and display to each other and slowly get closer then they would spin around each other biting each others tails until 1 would swim away.....unfortunatly i lost 1 male when my heater blew out and him and 6 of my young female guppys died
I had balloon mollies who did that.
If that's what they are doing... mine were fine for a while, but I eventually removed the black male just because I was thinking I had ended up with too many fish...
But they only did this because they were fighting over rebecca who just gave birth...
Anyways, I've had lots of fish before with bites out of their tail. They all ended up ok. Keep the water quality good and you shouldn't have a problem with it healing up.
I'd take the one male back to the store if he is that aggressive or if you really wanted to keep him, separate him for a bit somehow. He might not be hurting them. My balloon mollies rub their nose/mouth up against the base of my female's stomach then slowly move up on her and then, you can guess what happens.
Maybe he is just trying to breed with them and the others died from the move or the new tank or something.
It might be easier just to exchange him though. All fish have different personalities and most male platies aren't aggressive in my experience.
Sorry for the essay, goodluck! :)