Beautiful fish are the gymnos but they need a cooling period of around 3 months per year other wise they die quite easily prematurely between 1 - 2 years of age usually around 18 months old. If you could separate them into a tank to give them the cool period they need when they need the warmer period they should be fine with your keyholes.
Beautiful fish, pretty compatible with other fish but just difficult because of them needing the cool period.
These are on my to keep list, once Ive got my CAs and SAs separated I want to get a 30g for a group of some of the smaller species and also want to do a micro community in a 20g....
Wills