I ended up keeping both for the time being, they are getting along well now, minus the occasional chase here and there, but no more fin nipping! The one that was getting bullied is actually deformed, has a short body and a bent spine right before the tail, I felt bad for him/her and was given it for free with the first Guianacara. These guys have a TON of personality to them! Very lively and always the first to beg for food