Angelfishes (POMACANTHIDAE) are widely spread among coral reefs. They are very beautiful but their temper is not angelic. Each fish "patrols" the part of a reef and aggressively meets intruders, especially of the same or close species. It is impossible to keep more than one individual of each species in an aquarium otherwise the only and the most strong fish will survive in the incessant fights.
It is interesting, that the colouring of the young angelfishes differs from colouring of adults so strongly, that in some cases the scientists regarded them as different species.