Hmmm..Don't bother adding Melafix IMO. Melafix depletes oxygen and it will potentially worsen his labored breathing. Try dosing 0.3% solution of salt. Are the fins clamped? Start with a teaspoon per gallon of sodium chloride. Add another set in the next 12 hours and your third and last set in the next 12 hours after the 2nd set. Your front should be able to tolerate it. Make sure to maximize oxygen levels as well. If its fins are clamped and continues labored breathing, get praziquantel to treat for possible flukes.