missed the small part... sorry about that. the cardinals are listed in the thread.. I'd do some research on the ones listed. There are a lot of threads on here about this, and if I were to summarize what I've read it'd go something like this: Most fish school for protection and since we as good stewards tend to keep our fish protected, the natural instinct to school goes away in most aquariums. Chromis tend to be a shoaling fish rather than schooling (shoaling being more social rather than defensive) and it why they are sometimes seen grouping in home aquariums.