I simply refer to mine at "the pleco". I don't name my fish but my three year old daughter has come up with a few. Our first fish (a betta) was named Nemo. A couple months ago we picked up a blue betta, which she named Blue Nemo. She named one of my gold gouramis Mr. Gobby.
When we get a pleco we're naming it Meeni-Mu. It's pronounced mee-nee-moo. It'll probably be either a clown plecostomus or a rubber lip plecostomus, since those are the only plecs at our local PetSmart.
Also, quick question. Would a 4-5 inch pleco like a Clown pleco or a Rubber Lip go into a pirate ship prop that bubbles? We might move some of the bubbles though, so if anyone has a ship like that, let me know.