I have a 45G tank which has some fancy/ornamental goldfish as well as about 10 danios in it. About a week ago, the danios were up the top doing what looked like gasping for air. Unfortunately, one died, but the rest were back to normal within a day or so. Overnight my goldies have what appears to be some type of fungus on them. The temperature is about 20 degrees celcius. I know that there was enough oxygen in the water, because I run 3 airstones attatched to an undergravel filter along with a fluval canister filter. Attatched are photos of my black moore (Bethany) and my orange ranchu (Rachel) along with a pic of the tank. The other goldfish have it too, it was just easier to see on these two. It appears to be some type of fungus, but I'm not sure what type or how I should treat it. The water appears green, but it isn't. The background just makes it look that way. Thanks for your time and help!
Last edited: