yes they are all large angels, but, what would you like to know? I could ramble on forever. Body shape is the main thing. Size is about the same. If you are looking for scientific stuff, forget it, I am not that guy. I know how to keep them.
Coloration is a big deal but almost all of the big angels start with a similar pattern as a juvenile, the deep electric blue and white bars. From there, they morph into awesome adult colors. They are extremely territorial and will not tolerate a single fish of the same genus unless the tank is damn big. You can mix the genus' though, so it is very possible to keep an emperor, regal, and majestic (blue girdled) angelfish.
Certain angels are way more aggressive than others, just like tangs. regardless of the mix of angels, French, Gray, Blue Ring, and Queen angels are very aggressive and will likely not tolerate other angelfish regardless of the tank size unless HUGE, like over 300 gallons (Alexander helped me learn that one). Other angelfish are quite passive and will tolerate each other easily: emperor, blue-faced, majestic, regal. But, they tend to be extremely expensive as well. I don't want to ramble on forever without you specifying exactly what you want to know. Let me know if there is a specific I can try to fumble through...lol
-Doc
