Generally speaking, this match works pretty well because the rams stay very low in the tank. They tend to swim around right about the substrate. The angels are larger and swim up and down a bit higher,s o the 2 often don't even interact. Keep in mind, angels can be jerks so make sure the rams have a cave or something in case angels are being bossy. If there is no breeding, it is generally fine. If one or both species are breeding, just make sure each has space to feel comfortable.