Black Axil Chromis vs. Blue/Green Reef Chromis - anyone have any luck keeping a group of them?

[salty150]

Anyone have any luck keeping a group (5-7) Black Axil Chromis or Blue/Green Reef Chromis?

Anyone know if the Black Axil Chromis is "better" as a group in an aquarium than the Blue/Green Reef Chromis?

Would really like to have them - but from everything I have heard, read, and seen on YouTube, etc. about the Blue/Green Reef Chromis - they don't seem to last long in a group as they kill each other off.

The tank is 87" L x 30" W (255 gallons) and "medium" stocked - so they will have a lot of room...

 

[ISpeakForTheSeas]

I haven't heard about the Black Axil Chromis, but some people have had at least some success with the Blue/Green Reef Chromis (if you read through the links in the quote below, you'll find success is a mixed bag; there's some speculation as to why, but my guess/understanding of the factors involved is the quote in the quote below the links):

The following threads may be helpful here:

Keeping a school of chromis?

I'm looking at a tank upgrade to a much larger tank, and I've always wanted to have a larger (20+) school of green chromis. The issue is, every time I've tried groups of them (3-5) over the years, they inevitably whittle themselves down to 1 Alpha Chromis. Has anyone had luck keeping a school...

www.reef2reef.com

Let's talk about schooling fish...

So my 125 build has moved along nicely, and I've been thinking about which fish I'd like to place in the tank. I'm thinking I'd like to make this a tank which features schooling fish. I've been considering Cardinals to start. Also, I have been considering the Chromis. Any other suggestions...

www.reef2reef.com

And here’s a list of the general info I’ve been able to find about factors that likely influence schooling/shoaling behavior in our tanks (this is one of the posts in the first thread above):

My understanding is that keeping a large school can theoretically work, but - as mentioned above - there are a number of things to keep in mind with schooling:

- The number of schooling fish in the tank (I've heard odd numbers are preferred, and the preferred number of fish that I've seen seems to be 9 to 11 at a minimum; the more fish, the more diluted the aggression is between them)

- The size of the tank (for quality of life purposes for your fish, bigger is better - yes, some animals will be calm when shoved into tiny spaces with large numbers of conspecifics where if there was just one or two conspecifics, it would be a deathmatch, but they obviously wouldn't be happy in that situation long-term)

- The amount fed, the quality of the feed, and the frequency of feedings (basically more food = less aggression; and better food = better health = happier, less aggressive fish [theoretically])

- Tankmates (big, scary tankmates that the schooling fish could view as a threat may act as an outside force that keeps the schooling fish focused on not getting killed rather than on fighting amongst themselves)

- The scape of the tank (lots of fish need lots of places to hide/sleep - the more hiding places, the safer the fish feel; line-of-sight-breaks can also help with feeling safe)

That's all I've got for the moment (and pretty much all of it has been mentioned above), but basically - to my understanding - it's a balance of making the fish feel threatened enough by external sources to prevent infighting while also making them feel safe enough (largely through their numbers, the tank's scape, and food security) to not be too stressed. If you're able to strike that balance, you should be able to see schooling behavior (to the best of my current understanding).

I've also heard that you need to make sure you're getting Chromis viridis (one of like three species commonly known as blue green chromis) for them to not kill each other off.