White areas on pleco?

Have you ever seen the pleco behind the heater at all?
 
Nope usually he hangs out in his cave all day and then at night he sometimes comes out and sits on the ground but usually 24/7 in the cave.
 
Does he have white all over his skin? Have you added any new fish recently? And what results do you get when you test for ammonia, nitrite and nitrate?
 
Is it there all the time? My pleco gets patches sometimes but it is just his "camoflauge" (sp?) colors....
 
Looks normal to me as well. Just slightly changing colors to blend in better with the light colored gravel...this is just a guess though.
 
my gibby gets washed out like this depending on his mood...
 
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