Freshwater shark was been bitten

Question
To whom it may concern

I have my iridescent shark for almost 10 months, and so far everything it's been good until today when i got home I caught another fish biting on my shark, it lost some skin close to the first dorsal fin, and you can see a little bit under it's skin.
My question is there's any medicine that i can use and treat the fish, it's my favorite fish and I don't want to loose him.
Can you help me

Answer
Eduardo,

Yes there are a couple of things you can do. The first is to separate the fish. If it is happening now it will continue to happen even after the shark is healed. The other fish, what ever kind it is might not be compatible to the shark. But, I cannot say for sure since I do not know what the other fish is. One simple thing to do is a salt water bath. Take a one gallon container and dissolves 1 teaspoon of aquarium salt. Only when the salt is dissolved, you add the shark to the water. Make sure this water is the same temp as his tank. Let him swim in it for 15 mins to half an hour twice a day for a couple of days. Make sure you make new salt water every time. NEVER let him swim in the same salt water he swam in before. This should aid in healing and fight off any infection that might come along. If after 5 days there is no difference in your shark you can get Melafix and follow the directions on the bottle. If after 5 days there is no change or he gets worse let me know.