Looks a bit like mine, although mine is darker - Hypostomus Punctatus Pleco
It's disputable how big these grow. Mine is around 5" and has not grown in the last few months - we bought him at around 3".
They can grow up to 8"-12" in larger public aquaria and the wild, but rarely reach that size in the home aquarium.
Now i did a search on google for this catfish, and it comes up as Common Pleco alot, as far as i am aware Hypostomus Punctatus Pleco is not a common.
Several books i have on suckermouth catfish identify this as a different species/fish....
The books could be wrong i guess.
CFC is the man you want to ask.... im sure if he pops by he will correct me and tell you what the fish is.
From the small/medium image i would say Hypostomus Punctatus Pleco or possibly a Common.