Gill Disease In Peacock Cichlids? What does it look like? How To Treat??

I have noticed some deep colouration in some of my cichlids’ gills. Particularly the peacock cichlid and the mbuna.
I don’t believe it is a disease but I’m wondering what it may be. I do keep up my water changes and believe my water quality is good. If it is how can I treat it?
Please comment in the comments and let me know what you think.
#aquarium #fishtank #africancichlids #aquariumfish #cichlids #fish