Looks like bloat which is an internal thing and it spreads fast with africans.I use to have fifty african cichlid tanks.I found that when a fish looked like your photo i would quickly remove it and quarantine the fish and treat it with medicated food.
its a parasite...somewhat like itch if i were you id remove all the fishes.. out of that tank into a medi tank treat the other fishes with parasite bacteria medi and then treat your main fish tank for up to 1 week + water changes it happen on my koi fishes before so.. pretty good game if you dont it will mean all your fishes are gonna die ALSO!!!
make sure you take out.. the CARBON + Nitrate + amonia.. or w.e u have to filter out the water.. those particles OUT and just let the filter run alone with water into it !!