Pleco still has mouth fungus!
Hi- my plecostomus is alone in a 20-gallon tank. He got mouth fungus. As per the pet store's recommendation, I treated the tank with API "pro series" Fungus Cure (containing 3 mg Victoria Green B and 30 mg Acriflavine per packet). I followed the instructions, treating twice, 2 packets each time (1 packet per 10 gallons), 48 hours apart, then did the 25% water change as per instructions. It's 5 days post water change and the fish still has a white cottony blob hanging down from his mouth.
What do I do next?