We have an albino oscar around 3 inches long in our 50 gallon tank (along with other fish and another oscar).
2 weeks ago we noticed that his top fin was looking rotten. The skin in between 2 or 3 little fin bones was gone and the meat at the base of the fin looked like it was burned.
Now, we watch our fish for signs of disease all the time, so the assumption is that it occured overnight, because when I was feeding them in the evening the previous day there seemed to be nothing wrong.
I wonder if the water heater is the culprit, cause it stopped working shortly after the issue with the oscar and we had to get a new one. (But I never heard of heaters burning the fish).
The LFS advised us to fish the oscar out once a day and rub in the medication at the wound (intensely yellow stuff, no idea what it's called in English - we live in China). We did so for a couple of days, and the spot started looking better, but he was so stressed out that we decided to just wait and see.
We added the same medication to the water in the tank (LFS advice) and it cured our second oscar's scale issues. So apparently it's some good stuff.
But the albino still has the problem.
He eats and swims around no problem, though he stopped eating for a day or two after being fished out and treated.
Any advice would be appreciated.
Nitrates and nitrites are normal, we checked, PH is ok too, water temp at 29 celcius.