It does look like damage. Maybe from the spiny catfish.What's on the mucosus head? Slime clumps or scars or damage?
Pretty awesome catifhs, Will swim around the tank even with the lights on. At around 8pm every night he starts going crazy and will swim up to the top and just do laps around the tank wanting food, and as you can see from the video he eats like a pig. He is very peaceful and pays 0 attention to any of my other fish.Lovely and lively indeed. Tell us something about its habits, traits, quirks, what not, what you observe / when you observe them, if and when you will.