Blue reef chromis

35% Off ! All WYSIWYG fish and corals
I've had 3 blue reef chromis for 2 years they were wild caught. They had been very peaceful until this week, now one is dead and another being attacked by the now dominant one. Why would one suddenly turn super aggressive? Other fish are fine and not being bullied by the reef chromis.


Staff member
It is a typical situation. Often happens exactly the way you describe. I suspect it has to do with one reaching sexual maturity and seeing the others as competition. Contrary to common belief they are not schooling fish and unless you have a very large tank one is the max that you can keep.
They use to always swim together in formation, not any more. I'm trying catch one and put it in my other tank before it gets killed. I really liked these fish it's a shame they get aggressive with age.