Hi my pleco has white marks on him. He is usually out and about in tank but was hidden for a couple of days. When he re appeared he had these white marks on him. They look like scars. Not raised at all. I'm thinking could they be heater burns, or is it something more sinister. Anyone got any ideas. Sorry the photos arent as clear as i hoped 
It looks like heater burns to me as well, but could possibly be from something else. What else is in the aquarium besides the driftwood? How often do you do water changes and are you adding dechlorinator. List your water parameters.
