goldfish
I didnt have any fungus, but......
3 years ago, I set up my very first aquarium. It was a 50 gallon tank, which I had 10 goldfish in. About a week after I got the fish, they started going to the top, gasping for air (I had a air pump and filter and the whole nine yards). Well, next thing you know, I had NO fish left. I asked at the pet store, and she told me to have my tank set up for 30 days before introducing any fish. Before you set it up though, make sure you clean it out with boiling water, to kill any and all bacteria in there. Also, I was told to put Cycle in the tank and aquarium salts. So, I did everything that I was told, exactly like I was told and bought 2 goldfish (nothing was mentioned to me about the space required for goldfish, but I did a bit of research on the net, so I only bought 2!!). It is now 3 years later, and I still have those same 2 gold fish, and they are doing great!!!!!
I am sure some people will tell you not to do what I did, cause it is probably wrong (we live in a small town, so sometimes I think our pet store lady isnt very educated........lucky if she has grade 12!!! lol), but I am just passing on to you, what I was told to do!!