You are right in your analysis Averynight. When it comes to a nice compatible community of fish, there are many other factors to consider. Many of the so-called community fish, depending on the source being cited, can be quite nippy. IMO a typical African community fish would be called an aggressive fish in a new world listing. There really is no consistency to the process. The whole concept of fish being territorial seems to be ignored unless it becomes extreme, as we see in a male Betta splendens. Another factor that is seldom given in listings is whether any aggression is interspecific, between species, or intraspecific, within its own species, or both. Back to the Betta splendens example, the aggression is almost completely intraspecific but people generalize it to make silly statements about the male betta being dangerous with all other fish. A territorial example might be the kribensis where a krib that is breeding becomes very territorial with any other fish within a short distance of its nest site but ignores fish that are more than a few inches away. It goes even further than that, a fish directly above the nest is largely ignored but a bottom dweller is in extreme danger, because kribs breed at the bottom. In a reasonable sized tank, a very nice male swordtail is a terror for another male swordtail but people happily go on mixing male and female swordtails in a 3 to 1 ratio to minimize the impact of breeding efforts on the females. Meanwhile the junior male gets the tar beat out of him by the dominant male.
