2cm might have been a hardier size. In a community tank make sure they can hide up under a piece of driftwood, a solid bit.
They are primarily algae and vegetable eaters so don't go feeding meaty stuff for discus or something or the bns will bloat.
Add a piece of zucchini or cucumber weighted down and place it close to the wood area where the bns are hiding.
Veg flake is also very good as they can catch that on the current and pin it down and eat it.