Name: Chromis viridis
Origin: Indo-Pacific, Red Sea
A very cute and generally harmless little fish. Very greedy eaters that cruise in the upper to middle region of the water. Ideally kept in small schools, some individuals may pick on other Chromis (they are technically a type of damsel).
I have 2 of these and the bigger one makes the smaller one stay in one corner of the aquarium. When I feed them the bigger one chases the smaller one so he can't eat!
I've been keeping Damsels exclusively in my marine tanks. While my Chromis have been among the most passive, I've noticed that in Chromis-only groups, they will naturally develop a dominance order and one will end up bullying the others. However, with other Damsel's that are also on the passive side (like my Lemon) they will become more passive. I now keep a larger Lemon with them. The Lemon never attacks any of the others, nonetheless this seems to curb the Chromis "aggressive" behavior. In fact, the Chromis will follow and school around the Lemon in what I can only describe as a Big Brother type behavior. The Lemon also makes a nice contrast in color with the Chromis.
Green Chromis really are not a challenge to keep. I have 4 of them and 3 out of 4 are always together. Normally what they do is 3 will swim around together for a certain amount of time while one stays behind and guards their cave. They take turns guarding so the guard and school are different every couple of hours. They do sometimes get attacked by my Domino Damsel, my Azure Damsel and occasionally my Clownfish, but there's never any damage and my Chromis don't care much. Also they are all real pigs, they eat most of the food in my tank before anybody else does. Lastly, they seem to have a good relationship with my Yellow Tang. The Tang would stop moving in front of them and then the Green Chromis would start to pick parasites off him. They're very cute little fish, easy to feed, forgiving and can sometimes be used to remove parasites.
Green Chromis are peaceful. They prefer to be kept in groups of 5 or more to feel safe. Unlike most fish who find safety in rocks by hiding, chromis naturally feel safe in numbers. Chromis have a strong relationship with branching corals. In the wild, if you find a patch of staghorn coral, you're bound to find green chromis. At night they will sleep in the branches. Chromis are planktivores. In nature they flourish on drifting phytoplankton and zooplankton.
I had 3 Blue/Green Chromis in my tank. They just hid out in the rockwork until feeding time. I have just recently added 2 more, and now they are totally different fish. They are always on the move and an absolute pleasure to watch!