He's right.. Especially if there's any size difference in the Chromis. I only have one remaining now. The largest. I doubt they would "School" together even if they were the same size, due to the tank size. I didn't have this forum to research when I made my purchase... If so I would have been forewarned... Apparently the term "peaceful, schooling fish" is used loosely. Maybe in like a 150 gallon.....