I read through everything on the wet web media site and it had some good info. It seems they will do fine in a group provided they were in the group at the LFS and there is enough space in the tank. The rough estimate I found is 20 gallons per firefish to allow enough "bolt holes" for them to sleep in, ect. I think some run into problems when the buy the fish from different sources and mix them into the tank at different times. I bought three of them and they haven't been more than a few inches from each other and are swimming out in the open. Plus mine are housed with very non-aggressive fish, that should keep stress to a minimum. I'll hope for the best!