Lol what a stupid "Quick Stats" there.. says the "Adult Size" is "Up to 24"" then 3 lines down it tells you that you can keep in a 10 gal tank.. wow Petco ftw!
As far as your pleco goes, I think people just want to see you having/raising healthy fish which actually makes your fish keeping much more enjoyable imho.. there are a ridiculous amount of pleco's out there, some meat eaters, some veggie eaters, some need both, and some need wood, some get big, some don't, some need warmer water, some don't.. knowing what species of "common pleco" you have would help you give your fish the best environment possible