Is topical rid fungus harmful to fish?

My molly has some fungus growing on his side and i have an emergency tank set up for him. Now i am not sure if i will give him the Rid fungus medication only because ive heard rumors that it can kill your fish and that i have had other fish die who were administered treatment. My question is if you think i should try the application again or should i just apply high oxygen levels and aquarium salt?