He's on the glass right now so I measured, he's 16 and 1/4 inches long. The thing that makes him so big though is his width. The only thing that I can compare him to is that is about the same size is those little 1 quart paint cans. He's about the same size around as that. It's insane.
Is there any way you can take a few pictures of just the pleco, maybe in relation to something we know the size of, so we can see just how big he is I mean!!!