The exact size of the pleco will vary depending on the species. Ask someone at the pet store how large the pleco will get before making a purchase.
[header] How to introduce a pleco to a goldfish tank [title] Ask how large the pleco will grow to be. [step] Although most pet stores will sell plecos that are only a few inches in length, you should know that they can grow quite large. Fully grown plecos can reach up to two feet in length.