I have about 20 pygmy corys in my 46 BF community yank. I also have a group of 9 neons, and my pygmys are out all the time, schooling with the neons. The tank os moderately planted, with driftwood and caves. There are also 11 plecos in the tank, 3 x L104, 4 x L340 and 4 x red ancistrus. Never had an issue, and they've all been together for well over 2 years. Good luck.