Who Gives A Fish Forums

Just over a year in with my 240lt tank and I'm having some issues. Got a copperband butterfly fish recently and it's not going down well with my naso and yellow tang. I know fish can be territorial, but I thought these three were all pretty chill. Will the bullying ease off once they get used to the new bloke?

The thing is, your naso and yellow tang have already staked their claim, and the copperband butterfly's similar body type and color are probably setting them off. The tangs are basically treating the copperband like a rival male, hence the aggression. Unfortunately, it's unlikely this behavior will change as long as the copperband's in the tank.

fleeton wrote: ↑Sun Apr 27, 2025 12:59 pm The thing is, your naso and yellow tang have already staked their claim, and the copperband butterfly's similar body type and color are probably setting them off. The tangs are basically treating the copperband like a rival male, hence the aggression. Unfortunately, it's unlikely this behavior will change as long as the copperband's in the tank.

Cheers for the advice, I really appreciate it. I'm getting a bit desperate, to be honest. Would rearranging my live rocks to break up the territories help at all? I'm thinking of giving it a go, like starting from scratch. It'd be a shame to get rid of the copperband, I think he's got loads of potential and could be a great addition to the tank.

It's definitely worth a shot, and I can see why you'd want to try and make it work - that copperband's a great addition to your tank.