So I have a problem... I currently have a 4-5inch rainbow wolf fish in a 55 with 2 eheim classic 600, my problem is that when I turn on the air pump the wolf fish starts breathing hard (it's gills start opening wider as if its lacking oxygen), so i tested this and turned off the air pump the fish seems to prefer this, but I've tested with small feeders and they gasp for air at the top of the tank and then die from suffocation. So anyone know why this is? Seems weird to me because other fishes that I throw in there will suffocate, but the wolf fish prefers no air pump? Any ideas would be helpful.
Thank You