Hello all, I've had this problem on and off Since June now, the water seems to be testing fine (today it's tested ph 7.2, Nitrates 5mg/l , ammonia 0). The PH tends to fluctuate, so I have a buffer and use ph down, but the fish still sit quite often. This only happens in this one tank, the others are fine and I don't have to adjust the ph in any of the other tanks.
This tank is a 20 gal with a 30 gal whisper filter. I do regular water changes every four days to keep nitrates down (I will be doing one tomorrow).
Today I notice one of the two gf appears bloated (he sits the most, always has). I don't know if this is dropsy or not. I'm so confused, the water tests fine yet they are always sickly

... could this be the rocks I'm using? I know rocks can sometimes cause ph fluctuations, but they are aquarium rocks... I don't know. Is there a certain brand of rocks that are best in gf tanks? I also use Cycle to help with the bacteria.
OH yeah, I have a bubble wall in the tank too so it is very aerated.
Any help is appreciated.
Thanks
Stasia