Hey Pam, sorry, oddball question. I'm guilty of stalking my fish. I've noticed a flap of skin just behind the upper lip. Malawis, if it makes a difference. This flap is almost invisible when the fish inhales. But when they push the water through the gill it comes down and seals the mouth off, kinda like a check valve. I've posted this question on my usual forum, googled on the moon even, can't find any info particular to cichlid, closest I came was goldfish. Just wondering if maybe you know what this "flap" is.