tail rot/ other fin problems

Question
i have had two of my gold fish and a bala shark die because the tails rot away on my glod fish and my shark had a red sore on his tail fin wat is the cause of that and wat can i do to prevent it from my other fish!NOTE: The gold fish are obviously not in the same tank with my tropical fish because of the water temp. differance!

Answer
Hello,

I can't honestly tell you what the red sore is, but I can guess that it is likely caused by a bacterial infection of some sort. You may want to try a general anti bacterial such as Melafix, or something stronger such as tetracycline or triple sulfa. Any of those should help. The same medicines can be applied to fin rot as well.

I hope this helps.

Good-luck,
From Stephanie