Blue Devil Damsels Gone Crazy!!

[MontanaRocknReefer]

Hi Everyone!!!
I have two blue devil damsels and have had them for over a year and they were getting along really well and it looked like they were going to pair up. One turned a real dark blue and the other one remained a lighter color and was slightly smaller.
In the last 4-5 months the smaller one is now the same size as the other one and it looks like hell has broke loose. The one that was the smaller one has turned on the other one and has the other five fish after him/her too.
You can see marks on the body and the fins and tail have been bit on as well. He/she stays up behing a powerhead or goes up inside my overflow filter box for my skimmer to escape the punishment of the other fish.
I am hoping once a pecking order is established again things will settle down. It just seems so strange that this would happen after a year together. Anyone have any other explanations for this? I really love these blue devils and hate to see anything like this happening to my inhabitants.
I guess we can expect the unexpected in a reef aquarium but it still takes one by surprise at times and makes your brain work overtime trying to figure it out! Johnny

[dark horge]

Hi Johnny, I'm, sorry no one has picked this thread up so far.

It's likely because Pomacentrid (Damsel)behaviour is tricky enough a subject in the wild. Confinement in a small glass box makes for all kinds of unpredictability

But generally, once a fish becomes a target for mob aggression, it's toast. Some reefers try to provide refuges (PVC-pipe "caves") for the victim, but then the animal still remains at a permanent disadvantage around feeding time.

Good luck.

horge