I have had a pair of false percs in my tank for 3 years with no issues at all. They have gotten along perfectly fine until about a week after adding a yellow tang to the tank so mabye the new addition caused the change in behavior. I happened to be working from home a few weeks ago and heard quite a bit of splashing from the tank behind me. I turned around only to see the male attacking the female pretty viciously. He had completely ripped off her anal fin, the majority of her tail fin and one of the dorsal fins, and had pretty good chunks out of both pectoral fins. I netted her out and put her in the sump where she's been for about 3 weeks now. The fins are all recovering nicely and she's looking much better overall but i'm not sure that I can put her back into the main tank without the male attacking her again. Any advice? My wife volunteered to take care of her in a classroom setting so I do have an option besides just trading back into the lfs.