Originally Posted by
BlackAndRedLipstick
So, I have my 5 discus all varying sizes from 2.5 inches to 5.5inches or so. I also have them mixed with 3 black ghost knife fish. My tank is 60 gallons and everyone gets along fine for me. (this is just my experience with them.) My BGK seem to interact with each other and mostly leave the discus alone. Of my 3 BGK 2 of them are roughtly 2 inches and the other is about 3.5. When I first added the BGK they pecked a discus 1 or 2 times then just proceeded to leave them alone. Maybe i just got a lucky batch of BGK but that's my experience. My water conditions are 0-.25 Nitrate, 0-.25 Ammonia, and 6.5 Ph. Hope this helps.