All the Chrome - ok, maybe not "ALL"

Lets talk about 2 nearly ubiquitous saltwater reef schooling fish called Chromis. More specifically, Chromis atripectoralis and the nearly identical Chromis viridis. These two fish were have been mixed together both in the wild and in the LFS for decades. It isn't until the last 15 years or so that we started to differentiate them. Adding to the morass is that both of these fish have been called “Blue Green Chromis” at some point in recent history. These small turquoise fish are reliably visually separable only by the black spot at the base of the pectoral fin on the C. atripectoralis, and the lack of such on C. viridis. The world now calls C. atripectoralis the Black Axil Chromis, and we call C. viridis the Green or Blue Green Chromis. This makes a lot of sense, as the Chromis means “fish” and viridis translates to modern English as “blue green.”

As far as captive husbandry of these animals, they are both excellent choices for the home reef aquarium. They both remain small and are basically no risk to sessile invertebrates. In the wild they are found schooling tightly around branching coral and rubble with many places to hide. Similar displays in the home aquarium will reduce stress for the group. They do not need a huge amount of space, and will do pretty well with most tankmates, except those that are very aggressive, and large mouthed things that will consume them. They segue quickly and easily onto prepared foods like frozen mysis, finely chopped seafood and high quality pellets.

They do well singly in small aquaria or in large groups in bigger tanks; mixed or single species groups are both effective. Their natural schooling behavior is a little antagonistic and as such if you decide to keep more than one, it should be a group, the more the merrier. Frequently around the internet you will see exact figures of how many makes a good group; in our experience, nearly all of these numbers are too low. We suggest a bare minimum of 7 Chromis for a “school,” with groups in the teens being much happier long term if you have the filtration and space for them. Larger groups are also more likely to retain the tight grouping we frequently see and like. We've seen home displays that had more than 50 of them and that is a stunning sight!

So which one is better? This is a question you will likely get multiple answers from depending on who you ask. In our decades of importing these fish, we've found that the vendors we get them from and the time these fish spend in transit impact their chances of success much more dramatically than species. As a result, we offer Chromis sp (a mix of both species) from our SSC (Short Supply Chain) vendors that perform amazingly for us in house. They may cost a little more than fish that travel further, for longer, but we've found that is worth it. How do you get them? Easy, just have your LFS ask their sales rep about SSC Chromis for you and let us take care of the rest.