I would say yes, He would be best put into a ten gallon tank with just a heater for Quaranteen and given an antibiotic and anti-fungal together for not less than 7-10 days.
Here are some good choices, the important part is to get him out of there so it wont spread and keep the water clean and stable and the fish non-stressed
The first is an antibiotic, the second a anti-fungal, they usually go hand in hand these diseases fungus and Gram negative Bacterium infections. (Aeromonas, Pseudomonas, Flexibacterium Columnaris, AKA Mouth fungus AKA Saddleback Disease, ect )
Kanamycin + Furan2
Oxytetracycline + Methylene Blue
Maracyn-2 (minocycline) + Methylene Blue
I think your fish is in the early stages enough to be cured, And its not a bad idea to keep these meds on hand if one fish is showing it, but i can guarentee you clean water alone will not cure this, nor will the "FIXs" like melafix and primafix, you need something strong as its a somewhat tough disease. But it can be cured if caught on early enough and using powerful antibiotics.