Why do Green Chromis hate each other?

[FiveGallonSea]

In my opinion a school/shoal of Green Chromis add an amazing layer to any reef tank. I love how they are top swimmers since most fish are middle and down and they always stay together. Under my AI Prime HDs they shine. I just can't keep them in a decent number. I started with 5. They behaved for like 2 months then in 2 days 2 members were killed. I found them chewed up with labored breathing and just removed them to a bowl to have a peaceful death.

So I thought, ok let me try this again. Bought 3 more. Now I have 6, an even number, compared to the 5 I had before to try something different. 1 I witnessed dying during lights off the first day which I assumed was just because he did not acclimate well. The other 5 were fine, always together, for a month or 2 again and just like that 2 more deaths in 2 days. What gives?

I've read about this happening a lot, but no real explanations why. Anyone have any ideas?

Thanks

 

[Flippers4pups]

I

In my opinion a school/shoal of Green Chromis add an amazing layer to any reef tank. I love how they are top swimmers since most fish are middle and down and they always stay together. Under my AI Prime HDs they shine. I just can't keep them in a decent number. I started with 5. They behaved for like 2 months then in 2 days 2 members were killed. I found them chewed up with labored breathing and just removed them to a bowl to have a peaceful death.

So I thought, ok let me try this again. Bought 3 more. Now I have 6, an even number, compared to the 5 I had before to try something different. 1 I witnessed dying during lights off the first day which I assumed was just because he did not acclimate well. The other 5 were fine, always together, for a month or 2 again and just like that 2 more deaths in 2 days. What gives?

I've read about this happening a lot, but no real explanations why. Anyone have any ideas?

Thanks

In our inclosed systems, they can't escape each other like they can in the wild. They will exert dominance within their group.

The other thing about them is they are prone to contract uronema, which is contagious and likely deadly.

 

[Jesterrace]

A Combination of many of them shipping with disease these days and the the reason flippers4pups gave about dominance and having no where to hide. For these reasons I talk most who are looking into chromis out of owning them as they end up being more hassle than they are worth.

 

[davocean]

I agree poor handling and disease is a big factor.
I have seen such a split among long time reefers on these guys, but personally I've always had them and never had a problem keeping them, my longest run were 6 I kept for 6 years, and only lost them to equipment failure, but I've had many groupings in various tanks over the years, and I know a lot of other people that keep them long term as well.

I also don't buy into any odd or even theory, I've had both odd and even groups.

 

[davocean]

These are those 6 I had 6 years, you can kinda tell age by size based on tangs next to them.
I always get really small ones from the start, not sure if that makes a difference or not.
Mine even adapted to my anemones and shared them w/ my clowns.

 

[eatbreakfast]

I also haven't had an issue with them killing each other off, but I have high flow, feed frequently, and have lots of places for individual territories. However, there are many fish that are social in the wild, but not in aquaria. Bangaii cardinals and quite a few tang species leap to mind. As said above, in an enclosed system and with limited individuals social aggression doesn't get spread out.

 

[mdrobc13]

I tried to add 13 to my current school of 9 and ended back up with 9 about a week later. Tried to go for 16 and ended back with 9 so I gave up. Agree beside disease it seems like they do knock off each other from within the school from time to time. Crazy but seen it twice....so my divine 9 is good to go for now!