rubber lip pleco

I had a bloom of algae. It nearly covered my walls. I have a 20 gal, planted aquarium with a few bloodfin and neon tetras, a fiddler crab, and an angelfish. I went to my local Petsmart and got a Rubber Lipped Plecostamus (suckerfish). Unlike the black ones he only around 4-5 inches (from what...