Gone Aggressive

[The Rugger]

Hello Folks,

I have had a pair of Blue Reef Chromis for months now and just recently one has become very violent towards the other. They were added at the same time and for months would swim around together. Now one has resorted to hiding only come out to grab a quick bit during feeding time and display the wounds provided by the other.

Why the change in attitude? I read up and chose specifically because they were none aggressive.

Any insight is would be most helpful.

[graphixx]

that is very odd. chromis are usually a very communal fish with a very good disposition. I wish I could offer some help in that problem but I would not know what to say.

well actually......... is there a big diff in the size of them that may be a reason.

[The Rugger]

They are the same size.

[Gohn]

How about changing your rock placement and add 1 more Chromis. I hear that a group of 3 is a good amt. and it will change the dynamic with more to chase and split the aggression. It may even stiop it. The moving of the reef set-up will change + confuse the alpha fish + it's dominance over a particular comfort zone and territory. Nothing is guaranteed but you may want to think about these few suggestions. + Good Luck!

[The Rugger]

Good thoughts Gohn. The dominate behavior has subsided for some reason. They seem to be back to their old selves. I didn't do anything. Moving the scape around would be a major pain at this point, but adding another Blue Chromis would be doable. I haven't had much luck finding them on the East coast but I haven't looked in a while either.

[DanRF]

Chromis tend to whittle their numbers down one by one. I've only heard of a few sucess stories when trying to keep them in groups. The weakest will slowly decline in health, then when that dies, the next one will go the same way.

Much better shoaling fish are threadfin cardinals which have beautiful colouration and shimmer fantastically. They also hold well together in a group and don't display such in-group agression as other shoaling fish.

HTH
Dan