Why do green chromis fight with each other?

[Oliver199234]

Hi guys,

I saw my alpha green chromis attacked smaller ones. Is this normal? I thought they are a schooling fish.

I had 4 green chromis, 1 died and another has some physical injury. These fish are in my tank for 5 months.

My tank is 3 feet long with:
1 Blue tang
1 Bristletooth thang
2 clownfish
1 bicolor goby
3 green chromis

To be honest, there are plenty of space for them to swim around. I still don't understand why would they fight each other. They are supposed to be super easy to care for.

This started 2 weeks ago. The only difference is I changed my feeding schedule from 4 times (smaller portion) a day to twice a day.

 

[Doctorgori]

I had 4 green chromis, 1 died and another has some physical injury. These fish are in my tank for 5 months.

yes this is normal, and IS the norm unfortunately…
You start with 6, then 5, then 4 until they have knocked each other off till one is standing…
Perfectly normal for these fish..

Although seems more hobbyist get a school to work anymore…

I’m not one of them, so here is a bump
Added: I did get the dark blue Florida chromis to work for a hot minute…but not really … still sometimes they are easier, but I’m told that’s temporary

 

[BristleWormHater]

Many people start with a few chromis and end up with one. Unless you have a very large tank, it usually goes like this. This is the same reason I decided not to put them in my tank.

 

[Dan_P]

Hi guys,

I saw my alpha green chromis attacked smaller ones. Is this normal? I thought they are a schooling fish.

I had 4 green chromis, 1 died and another has some physical injury. These fish are in my tank for 5 months.

My tank is 3 feet long with:
1 Blue tang
1 Bristletooth thang
2 clownfish
1 bicolor goby
3 green chromis

To be honest, there are plenty of space for them to swim around. I still don't understand why would they fight each other. They are supposed to be super easy to care for.

This started 2 weeks ago. The only difference is I changed my feeding schedule from 4 times (smaller portion) a day to twice a day.

Funny thing is that my well fed 7 Chromis (only fish in 75 gallons) do not exhibit too much aggression. I suspect hungry fish tend to be more aggressive. Since it seems this hobby tends to under feed (in the name of controlling nutrients) and overstock their systems, I am not surprised there are fish that become aggressive under these conditions.

 

[Tamberav]

Our tanks are tiny and it is difficult to replicate their schooling behavior in most tanks. They do tend to fight.

 

[slingfox]

I have had 11 chromis in my 110g display tank for almost a year now. The key is I have a Bimac anthia male which keeps the chromis in check by chasing them around every so often. That keeps the chromis from fighting each other. I also feed 5x a day. Why did you reduce feeding from 4x down to 2x? I just do small feedings more often. Helps keep the tank peaceful.

 

[boacvh]

Because they are Highlander, there can only be one!

 

[Peair]

Hi guys,

I saw my alpha green chromis attacked smaller ones. Is this normal? I thought they are a schooling fish.

I had 4 green chromis, 1 died and another has some physical injury. These fish are in my tank for 5 months.

My tank is 3 feet long with:
1 Blue tang
1 Bristletooth thang
2 clownfish
1 bicolor goby
3 green chromis

To be honest, there are plenty of space for them to swim around. I still don't understand why would they fight each other. They are supposed to be super easy to care for.

This started 2 weeks ago. The only difference is I changed my feeding schedule from 4 times (smaller portion) a day to twice a day.

Yes, it happened to me already, they were 5 bucks a piece on sale, I bought 7, and in one week only one big one left.

 

[Doctorgori]

I suspect hungry fish tend to be more aggressive. Since it seems this hobby tends to under feed (in the name of controlling nutrients) and overstock their systems,

….OMG this is soooo true ….

Although TBH I’m one of those evil 2x/day feeders…
but you shouldn’t expect Anthias, Chromis or some of the plankton grazers to be biologically setup for minimal feedings

 

[west co reefer]

Im assuming aggression due to survival instincts. They need more frequent feedings or they'll kill off competition to give themselves a better chance of survival. In nature these planktivores feed very frequently.

 

[robertmosen]

Hi guys,

I saw my alpha green chromis attacked smaller ones. Is this normal? I thought they are a schooling fish.

I had 4 green chromis, 1 died and another has some physical injury. These fish are in my tank for 5 months.

My tank is 3 feet long with:
1 Blue tang
1 Bristletooth thang
2 clownfish
1 bicolor goby
3 green chromis

To be honest, there are plenty of space for them to swim around. I still don't understand why would they fight each other. They are supposed to be super easy to care for.

This started 2 weeks ago. The only difference is I changed my feeding schedule from 4 times (smaller portion) a day to twice a day.

As a species they are easy to care for and can survive many beginner misstakes.

As young they school but when sexually mature they stake out a part of a reef as it’s territory. Each adult fish need about a square meter in the wild, this is not possible in most tanks for obvious reasons. This is why they fight.
Almost every chromis species behave like this

 

[Doctorgori]

As a species they are easy to care for and can survive many beginner misstakes.

As young they school but when sexually mature they stake out a part of a reef as it’s territory. Each adult fish need about a square meter in the wild, this is not possible in most tanks for obvious reasons. This is why they fight.
Almost every chromis species behave like this

this is pretty close to what I was told by a Florida collector. He almost said this verbatim about the blue chromis

I think folks see schools on the reef and not actually realize how much space is actually between the fish… Those schools of Idols and yellow tangs must be in hundreds of gallons of water, yet it looks like we can fit 10 in a 300g