Hi. Corys really like to be in bigger groups, five plus, and a Bristle nose is a bit big and a heavy spoiler for a 20 gallon. I would drop the BN and increase the Corys. I can see the attraction of having both, I have a BN and about 12 Corys in my 55 gallon. The more Corys I add, the happier they are. I inherited the BN and would have gone for a small species fancy Plec but I can't get rid of the BN now that I have him.
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