That's not correct - although with large aggressive SA/CA cichlids it might happen.
Smaller species of SA/CA cichlids have co-habed in my Charciform tanks just fine. My old SP. Peru lived with a breeding pair of Salvini.
My Gold Wolves and Black are with two Geophagus Brasiliensis. Its risky with a Hoplias Sp. but ery and Hoplerthrinus would probably be fine, as long as the cichlids aren't big enough to eat them or bully them, or small enough to be eaten.
It's 50/50 depending on the mood of your wolf have you ever thought about petting him just think about the fish that have to live with himMy last wolf was 14" and he ate my 8" Doviiwith no problem so good luck