Something Wrong With Bn Plec?

[SecretlyaZombie]

I bought a male BN plec about two months ago and have barely seen him, he hides under his bogwood most the time. I feed him every other day one Tetra Pleco multi wafers. I haven't seen him eat one yet but I bury it in the sand, (not too deep) where he's hiding (so that the tiger barbs don't steal it) and it's gone every morning. Should I feed him more or less or more variety? I try giving cucumber but he doesn't come out for it, i've seen him have a few peas though. It's difficult feeding him with the tiger barbs though. ):
Today, he was swimming around the tank whilst the tank light was on which i've never seen him do, he wasn't bothered much when I came to take photos as I noticed his belly looked huge and there's a lump below it whichb I hadn't noticed before, I couldn't find a photo to compare it to another plec so I don't know if it's normal. I'm quite worried.