Chromis killing each other, won't school

[zachfishman]

So far I've tried twice to get a group of Green Chromis to school. Both times I bought five fish; tried it in two separate tanks. Each time they loosly schooled but the smallest one was always harassed. It would eventually die, leaving the next smallest to the same fate until two were left, one swam freely and the other slid about the rocks. What's going on? (definitely not because of other fish)

[ChasingPuck]

Chromis are in the same family as damsels--they are not friendly, happy fish. They will school in a big enough tank--the only success I've seen has been in tanks larger than 250 gallons with lots of coral heads.

[grim]

My chromis schooled for a month. Then they systematically killed each other off one by one. In nature, this is probably a very good survival methodology to ensure only the strongest live to reproduce. I'm going to wager a super wild guess that their reproductive rates in nature are just slightly higher than their kill-off rate. But, when you take a few of them, put them in an environment where they won't reproduce, you'll eventually end up with one or two. I've also heard some anecdotes about large schools surviving longer because aggression is spread out a bit, but who knows.

Moral of the story, chromis school when scared, kill eachother when comfortable.. They are so cute though, who knew..

jb

[Aged Salt]

My experience is similar to ChasingPuck--have 22 in my 375g SPS tank. Because I feed my Bartletts 3-4X/d, they seem to be less aggressive toward each other,Bob

[technoshaman]

I bought 7 chromis for my new tank , one croaked on the way home and the others schooled in terror possibly from seeing my tuskfish. Once they figured out most of the fish in the tank are sissies they are all over the place and never school anymore. No threat - no advantage to schooling. I would net them all and trade em back in except they still make a nice display and are kind of entertaining.

[naesco]

I have had the same problem.
What I do is take the the one that is getting picked on a put him in the refugium for a while.
When she gets much stronger I put her back. Do not leave it too late.

REEForm: Never buy a fish from the Philippines or Indonesia where the use of cyanide is rampant

[Aged Salt]

Not sure if it's my #'s of chromises or a few lg. fish in the tank but mine "group" almost across the entire 7ft. length near the top, thus making a fantastic reef display