Chromis School

[BlueTang<3]

I have seen this done in large tanks, assuming your tank is the 33 gallon in your signature I wold say your always going to have this problem. In our 180 we had problems keeping a school as the aggressive one would eventually take over.

[fishytime]

see.....the problem isnt with the chromis......the problem lies with what the majority of people think is a school.....we add 6, or 10, or 20 "schooling" fish and think we have a school.....these fish school naturally in numbers far larger that we aquarium enthusiasts could ever hope to house......what we have when we add 10 chromis, is a small group, so what usually ends up happening is you end up with significantly less than what you started with, after one fish establishes dominance........another factor is the lack of presence of large predatory fish(or perceived to be predatory), keeping the schooling fish feeling the need to school......

[chewie]

I read somewhere to keep them in odd numbers. 3-5-7 ect...Not sure why but seems to work for me. I have 5 in a 90g reef and no problems. I actually took two out and put in my other tank(100g) and the three had no problem and the two together did seem to fight a little. I put the two back in the 90g and the other 3 seemed so excited to see them. Swimming around like crazy and "greating" them. No problems at all.
They are green chromis by the way. I was thinking of adding some blue chromis to the mix to see what happens.

[Maverick00]

Originally Posted by chewie

I read somewhere to keep them in odd numbers. 3-5-7 ect...Not sure why but seems to work for me. I have 5 in a 90g reef and no problems. I actually took two out and put in my other tank(100g) and the three had no problem and the two together did seem to fight a little. I put the two back in the 90g and the other 3 seemed so excited to see them. Swimming around like crazy and "greating" them. No problems at all.
They are green chromis by the way. I was thinking of adding some blue chromis to the mix to see what happens.

funny you mention that because i recall reading something very similar awhile back. However i guess 33 gallons isnt enough to keep these guys happy.

[Maverick00]

^ very interesting.

Well the first time i added a group of chromis was a month or two after buying this tank second hand along with no knowledge of saltwater whatsoever so i assumed the lost fish could have been the cause of bad water parameters. Now that i have a basic understanding of water chemistry (12 months almost to the day!) i figured it may have to do with behavior and dominance. Thanks for the comments guys, i think ill be holding off on trying this one again until i have a much larger tank.

[Lance]

Numerous small feedings throughout the day will help lower the aggression.

[Snappy]

I have kept a "school" of the same 15 or so chromis successfully for over 2 years which breed & spawn like crazy but it is very difficult to achieve good results with a smaller tank.

[ALang]

I have had 13 or so in a 130g. They never school together like I thought they would. They usually hide behind rocks, powerheads, etc, separately. They are now down to 7 after two years.

I read somewhere they like to graze all day long on tiny planktonic foods, and since then, I have fed them with freeze-dried cyclopeeze, "Reef Chili", Acan Plus, and even Combo-vital.
They do love picking these food off the surface and water column.
HTH.Lenny.

[Navarchus]

The problem is that when a breeding couple is formed the male will kill the competition

[loveless]

In my opinion chromis are not schooling fish like everyone seems to think. I went to fiji on vacation a couple ofyears ago and witnessed chromis in their natural environment. What I saw was alot of schools of chromis but they were small fish up to about 1 inch. As the fish grew larger I didnt see any schools at all. I did see the adults everywhere but in singles only. So I firmly believe that what we see as schooling habits are just a juvenile thing and as they age they turn into solitary fish.