I have 2 male blood sword tails, and they are picking at 12 of my rasboras occasionally, and frequently picking at my 1 dwarf gourami. i added a bunch of plants and made one corner very dense with plants, the gourami is fine now. but i'm worrying about the harlequin rasboras.
Ammonia 0
nitrate under 20
ph 7-7.5
40 gallon tank