Can you add salt for fish tail rot?

You can add salt for fish tail rot, but it needs medication too. Tail rot usually follows parasite damage then bacterial infection, turning the fin white and splitting at the end; in severe cases the whole fin rots away. Fish of all ages can be infected year-round.

Salt disinfects the tank, but also change water promptly to improve quality. Apply malachite green dissolved in water at 1 percent concentration to the affected area once daily for 3-5 days, then use a furazolidone bath.