For the time being I am holding off on adding the Otos to my 20 gallon. With my current stock of fish the tank will be at 101% capacity according to Aqadvisor once the fish reach adult size.
My little bristlenose has settled in nicely. There is some green algae, but I am also supplementing with algae wafers and various veggies (so far the cucumber has been a big hit with him).
He does spend a great deal of time nibbling on the underside of the driftwood.
Recently I rebuilt a 40 gallon and after a few months , once it is a bit more established I may add Otos to it. I do like the Otos and would enjoy having some.