I'm growing out eight
Krobia guianensis right now and I'm amazed at how fast they grow. They are nothing like my Xingu. The Xingu were shy and took forever to grow (both batches!) but these guys went from 1" to 3" in just about two months and they eat EVERYTHING. Including tankmates, if they're hungry.

I learned this the hard way. I was growing them out with my 2" Geo parnaibae fry, and if they decided they were still hungry at the end of the day, they would attack and kill a Geo fry and eat it. Crazy!
I guess I will mix them with my Acaronia once I have my new tank set up. The Acaronia have taken eyes out of my Red Bahias. *sigh*