What are your water parameters? (ammonia, nitrite & nitrate). How long have you had the bristle nose? What else can you tell us about your tank---size, all fish & how long you've had them, water change schedule?
What, besides veg on a fork, are you feeding? He looks nicely chubby. I see what you mean on his upper side but I agree with OG, not alarming. Do a few water changes within a few days & see if that helps.
Hey thanks for the help but he is starting to go back to a good solid colour now think it might have been a bit of stress I put a new cave in the tank a couple day befor the change and found out it could have caused some stress all water reading are fine had them in the 4 foot tank about 1 year now I feed them algae wafers cucumber and some other greens as well think thanks for the help