The darker one (one the right) looks like a Pterygoplichthys disjunctivus to my untrained eye (it's the only one I know). If you really want to know for sure you can post top and side vews of them at this website and they will give you an answer.
In other words, you have 2 common plecos that get big. They eat algea and DRIFTWOOD. As they get bigger they will need more of a variety, including more protein.
They are actually both Pterygoplichthys, IMO. The larger one is a gibbiceps that will get 18" or so SL and the smaller one is joselmianus, which should grow to 12" or so. They're nice fish, congrats! They don't "eat" driftwood, but they will regularly graze any algae or films that grow on it.