I purchesed 5 Black Moore goldfish for my 72g tank on Sunday (3 days ago).

I noticed one of the fish was acting a bit sick so I kept an eye on it. Last night I noticed that there was a bit of white stuff around the side and back fin... but not much.

Today The fins that had the White stuff on them are almost completely gone.... I moved the fish to another tank ASAP... and did a water change in the main tank. The fish in the hospital tank is dying.

I'm noticing this thin string like white stuff in both tanks now... I believe one other fish is starting to show signs of being sick.

Any idea of what this illness is so I can treat it before they all die?

I can just bring them all back... but I'd rather treat them than let gosh knows what happen to them if I were to bring them back to the store... but if I don't know what it is then I will have no choice.


Thanks.

Oh yea... these are the only fish in the tank, the tank was well established but has been empty for a while. (Biowheels and all equipment remained running... and water changes were still done)