the blue green chromis, green chromis, and blue chromis are all the same thing. depending on whre you get them. reason.. they change colors depending on how the light hits them. providing you have good light.
mine change from white, to blue, to green, to purple, all while swimming from one side of the tank to the other.
ever seen that new expensive paint on fancy cars, that changes color? imagine that on a fish only brighter
and yes, very docile, and schooling. i currently have 3. bought 4, but one was eaten, i belive by a evil hermit that also was chewing on my star.
they are also extremely hyper and lots of fun to watch!