Endler's, sooner or later you'll WISH they'd eat their fry. I started with a couple dozen in a 10 gallon tank. Then they were moved into a 29, and finally a 40 because they bred faster than they sold. I finally picked up a baby (~3") Carapo knife fish at a CCA auction and dropped it into the 40 with the several hundred endler's. The Carapo thinned them down to a handful of little ones in a couple months, grew 2.5" in the process, and is now working on crowd control for my excess cutteri fry. A few of the endler's were moved to 2 other tanks, a 10 and a 30, and their numbers are gradually increasing again.