My fish are all not as active, hovering in the water with fins clamped, and some of them flicking against things. The tank is 9 months old, fully cycled. Had some sort of disease outbreak a few months ago when I introduced a new fish, lost over half my stock. I can't see any other obvious signs of disease on them. Will post water stats later before I water change. Only thing that seems to be doing well is my shrimp population. Any ideas what's up? & advice?
I did a water change yesterday and cleaned the filters out but they're still flicking against things, the danios mostly - flicking against the sand.