2 of my angelfish are breathing rapidly on the bottom near the intake and heater tubes. They''ll swim around if you shoo them but are reluctant to move. I added 6 ruby barbs and that's when this started to happen. I gave them a fully cycled gravel bed of ehfisubstrate from an established canister filter and never detected any ammonia or nitrite.
please, any ideas?
55gal pH7.4 gh8 kh5 78F
thanks

please, any ideas?
55gal pH7.4 gh8 kh5 78F
thanks