Ah, yes I agree. I didn't look at the tank size. Shame on me. My pitbulls are in a 10 gallon now and they almost look cramped, but not quite. I'm thinking about moving them to a larger tank eventually. I wouldn't put a rubbernose in there. Pitbulls only grow to 2", though, so would be a much better choice. I think 20 gallons sounds like a good sized tank for a rubbernose. Ottos are sensitive to water quality and things tend to not be too stable in such a small tank so I don't know how successful you'd be with them.
Tammy
Uhm, sorry that I'm typing in such a fragmented way tonight. I guess that's just how my brain is working. I'm tired. I doubt my posts are even going to be any help! I think I'm just putting down thoughts and nothing really useful...