Many aquarium hobbyists who raise angelfish choose to cultivate angelfish-only tanks. In fact, angelfish tend to do best when kept in groups of 5 or more of their own species. This is certainly one option that will guarantee that your angelfish do not have trouble with aggressive tank mates.

How many angelfish should be kept together?

The aquarium size depends on how many fish you plan to have. For a 29-gallon community tank, keep no more than four adult angelfish with other tank mates. For a 55-gallon tank, start with five or six juvenile angelfish and be prepared to remove some in the future if they get too territorial.

Is it OK to have only one angelfish?

A single (male or female) would be just fine. Most Angels are just fine with other species as long as the other fish stay out of their breeding area. A single Angel will not have a breeding area, so that is OK. The fish you list are large enough not to get eaten.