Hi, I've received help from this site before, when I found myself, about 6 months ago, the unwilling and totally inexperienced owner of 2 gourami and 2 goldfish, delivered to my door all in a 10-gallon tank. Per advice from people here, I donated the goldfish to the pet store and kept the gourami. I also upgraded to a 30-gallon tank. The gourami lived very happily. Then 3 weeks ago, the blue gourami, a fish over 5 years old, died rather peacefully. To prevent the remaining gourami, also over 4 years old, from getting lonely, I bought a pair of younger gourami. All three have lived happily for the past 3 weeks. Now this one old gourami has had fin rot, along with something fuzzy on him, since I got him. His previous owner did not keep the tank clean. I do weekly 25% water changes, and his condition has stopped worsening but does not improve. In all his time living with other tankmates, the condition does not spread to other fish. I have treated the tank with numerous meds, both bacterial and fungal, and nothing clears up this grey-ish fuzz. It exists in two strips on each side, and a little on the fins. After giving up on the meds, I gave the gourami a salt bath last week--30 minutes in a 3% solution--and to my amazement the condition actually improved. The strips on his sides now have clear patches in them. I want to treat him again, but the poor guy is so old, and it stresses him out to get netted and removed from the tank (you should have seen him hide under his rock when the net came for him). I am considering either 1) leaving well-enough alone (after all, he is very old, probably near the end of his days, has had this fuzz for as long as I've known him, and seems to be getting along just fine as is); or 2) treating the whole tank with salt, so as to avoid having to remove him again. I've read all the debates online over salt in freshwater tanks, and I'm not sure what to do, so I'm posting here. Does anyone think it would help? Hurt? Maybe hurt the other two younger gourami? And how much salt? I've read 1 tbsp per 5 gallons, as well as 1 tsp per gallon. I think I would only treat the tank once--that is, I would not replace any salt with the next water change. I know this may kill my plants--I'm willing to sacrifice them if it will finally de-fuzz poor old gourami. Any opinions/advice on my proposed salt plan would be greatly appreciated.