They constantly bicker. They weren't bothering the other fish (demasoni, yellow labs, acei and cobues) but they were causing an overall feeling of stress throughout the tank. So I moved them into my grow-out setup, but then 1 of them got targeted by the other 2 and I lost him in a matter of a day. I separated the other 2 and they're fine tank-mates, but they need a larger tank to be together again. I suspect they'd be good in a 125, the 55 was just a bit small for them.
Glad to hear the red zebras are doing well. They're a great fish, and I got lucky to get a pretty strain.