very nice common plec, under fed but nice none the less.
i feed my gn,bn, and clown plecos on, potato, cucumber, algae wafers, shrimp pellets, non colored flake and dried blood worm cubes. i vary the foods daily to keep them interested and helps keep them fit and healthy. i aways feed a little more than what is needed to make sure they all get some, my clowns are extra shy. my routine at water change time consists of a thorough vac of the substrate and mild rinse of the filter/media.........just in case uneaten food is rotting away and spoiling the water.
i hope you have a nice big tank because this guy you have will indeed reach 18 inches plus.anything less than a 6ft x 2 ft ( and thats a tight turning circle! ) will be a stretch and cruel in my eyes. 7ft x 3 ft would be comfy.
EDIT:
just noticed your signature and that Clear Seal 106 litre tank wont hold him for long.if your like me and love plecos, you will get attached to this little guy very quickly, so in my honest opinion i would upgrade fast-ish or re-home the little fella.
mark