I read bio wheel filters don't need bubblers is this true?
One of the nice things about Bio Wheels is the agitation, surface area they provide for getting a good carbon dioxide/ oxygen exchange. For most, no added agitation would be needed. The air exchange even a small Bio Wheel provides is more than even a large "bubbler" can give.
Nitrate Poisoning Symptoms:
Fish gasp for breath at the water surface
Fish hang near water outlets
Fish is listless
Tan or brown gills
Rapid gill movement
These are pretty close to what a tank starved for air exchange looks like.
Just wonder if your “messing” didn`t let a nitrate spike loose.
Maybe a toxin was on your hands you were not aware of?
Best thing you can do in a situation like this is a massive water change.
Funny, how many bad situations can be made right by no more than a water change.
All Malawi,All Mbuna,All Action,All the Time