Shy fish

I have a pleco that I rarely see and I'm wondering if I'm doing
something that bothers the fish. I don't know anybody else that has
an aquarium so my only other frame of reference is the LFS. Whenever
I go in there, I see their pleco's attached to the glass, doing their
thing. Mine hides out in the castle. I will occasionally see him
lounging on the bottom of the ship, but he's usually tucked up inside.
I know he's there keeping the tank free of algae because it continues
to be gone once he did the original cleaning. I know they are more of
a nocturnal fish, but I guess I expected him to be out a little more.
I'd just like to see him out doing his thing because I enjoy watching
the fish do their fish things. Are they normally this reclusive?
Anyway to entice him out to enjoy more of the tank?

Thanks.