Can Only One Chromis In A tank Work?

[Fishfreak2009]

More like thirsty for blood.

I always found Chromis cyaneus much more aggressive, especially as they get larger. Chromis nitida tend to do the same once they hit maturity.

If you watch Chromis cyaneus on the reef, they eat non-stop all day, and even though they're schooling fish, they hang together more loosely as adults than Chromis viridis or the other smaller Indo-Pacific chromis species (i.e. Chromis vanderbilti and Chromis margaritifer) and are more nippy/aggressive with each other as far as bolt holes/hiding places. Put that into a tank where they get much less food than they do on the reef (increasing aggression since they aren't distracted with eating) and don't have space to all get away from one another, and don't have to hang as tightly together to avoid predators, and you end up with WW3 as the fish mature.

 

[blaxsun]

More like thirsty for blood.

No doubt. I have six green chromis right now and they're basically inseparable. Very peaceful, but I call them "the swarm" for obvious reasons. And they get fed 6x daily (2 fresh, 4 pellet).

 

[REEFTIDE]

One is more than fine

 

[Sean Clark]

I always found Chromis cyaneus much more aggressive, especially as they get larger. Chromis nitida tend to do the same once they hit maturity.

If you watch Chromis cyaneus on the reef, they eat non-stop all day, and even though they're schooling fish, they hang together more loosely as adults than Chromis viridis or the other smaller Indo-Pacific chromis species (i.e. Chromis vanderbilti and Chromis margaritifer) and are more nippy/aggressive with each other as far as bolt holes/hiding places. Put that into a tank where they get much less food than they do on the reef (increasing aggression since they aren't distracted with eating) and don't have space to all get away from one another, and don't have to hang as tightly together to avoid predators, and you end up with WW3 as the fish mature.

Great info.
Any thoughts on Chromis anadema? I would love a group of those in my reef.

 

[blaxsun]

Great info.
Any thoughts on Chromis anadema? I would love a group of those in my reef.

Those are super cool!

 

[Fishfreak2009]

Great info.
Any thoughts on Chromis anadema? I would love a group of those in my reef.

Seem similar to Chromis opercularis. I would assume they would get more aggressive and less friendly with one another as they grow, and if similar size to anadema, will be 6" as adults. I would say behavior would be similar to Chromis cyaneus, ok together as juveniles, but progressively worse as adults.

 

[madlos123]

I started with 7 blue green chromis in my 40 gallon 2 years ago. As of now I still have all the same 7. I have upgraded to a 90 gallon 5 months ago. Last month I added 5 new blue green chromis. The new ones are half the size of my original batch.

My original 7 are 2.5 inch to 3 incher while the new ones are 1 inch or less. They all shoal together.

All of them hang out together big and small out in the water column.

My 1st batch of chromis (7) was no problem, QT for 1 month that was 2 years ago.

My 2nd batch of chromis (7) was full of problems. QT time was 6 months, after ich, black ich, bacterial problems. Lost 2 chromis in this batch from bacterial infection 1 month after I bought them during qt.

In my opinion they can be very fragile once they get some bacterial infection.

I lost the 2 in my 2nd batch within 24 hours when the bacterial infection sets in.

You definitely need to feed more like 3+ flakes/frozen mysis or fish eggs per day especially when they are tiny.
Or they will fight with each other.

My 1st batch ate flakes right away.

My 2nd batch are problems.
The problem the 2nd batch is getting new blue green chromis also 0.75 incher is that their mouth is so tiny. I had problens getting them to eat my regular frozen mysis and fish eggs. I have to use crushed flakes, brine shrimp, and frozen daphnia. Then once they get bigger i upgraded to hikari mysis which are smaller than the san francisco brand. Then fish eggs when they realize it was food when the bigger chromis showed them its food lol.

Add them all in batches like 5+ at a time. Same method when adding new fish in Mbuna tanks.

Definitely start out with healthy blue green chromis to increase survival rates.

You also want to have a lot of hiding places for them to feel comfortable.

No other aggressive fishes that will nip them.

1 in 20 gallon is just fine.
I feel like 40 breeder is perfect if you get 5+ more. With lots of hiding places then upgrade from there.

Heres my proof video


Some of the blue green chromis likes their own hidey holes when they get bigger too so you might not see all of them swimming together.

 

[Twoddler]

I have 10 total and that has stayed the same 10 for 3 plus years. Key is to keep them well fed often to avoid constant picking.

Agree, although I feed mine once a day, theres lots of live rock and critters for them to munch at and hiding places, theres no trick to it , just the right environment.