There are not that many differences between them, other than physical, Hybrids will grow faster than regular blue gills, Blue gills are more round in shape to say a green sunfish or a red ear, Then you have the smaller sunfishes (we'll call them dwarfs) like the banded and the mudsunfish. But most of the popular game fish sunfish will all be about the same, and at certian times these will naturally hybidize, namely man made inpoundments. They stock many types to attract fisherman resulting in some hybrids due to uneven populations of one kind or another. We have many lakes here in pa that are like this, due to the fact this state only has one natural lake in it. I hope this helps a little.