In my 29 gallon, heavily planted,7.6 pH, no ammonia, no nitrites 5 nitrate (tested today this has been constant readings for weeks), almost all the fish are dead now.
In the last week I have lost (newly added) 6 hatchetfish - one looked like it's eye was fogged, other ones showed no disease, just died. 8 neon tetras dead - established for 6 months one had slight fuzzy growth on head for one day before dying. 1 oto cat - established for 6 monthslooked like it was wasting away for a day or 2 before dying; and this morning, one previously healthy acting and looking juvenile angelfish established for 3 months- yesterday it started acting different, hiding in the back of the tank but eating and not showing any outward sign of disease, this morning on the bottom almost dead, started floating and barely alive a few hours later - I removed and flushed. CAN ANYONE TELL ME WHAT IS HAPPENING AND WHAT TO DO?
REMANINING FISH -I have one juv. angelfish that looks and acts fine, 3 cory cats who look and act fine, one oto cat healthy and eating & many healthy cherry shrimp.
I treated the tank with melafix yesterday and today at the strong recommendation of the Petsmart person - I am now feeling foolish because I think I should have gotten Furan 2 or something similar but these fish are not showing very obvious signs of Columnaris. I also added the recommended amount of salt yesterday and lowered the temp. a bit after reading high temp encourages Columnaris.
I decided to make a 30% water change and expect everything else to die???