I have not treated my clown loaches for this, but for discus I used Metronidazole and Fenbendazole. If choose Fenbendazole, recommend use special no-taste preparation for dogs / cats which fish will also eat. Straight out Fenbendazole in fish food taste really foul and bitter (I have tried!), and my discus never ate it. Wow, 12 years old clown loach too awesome! Hope fish recover health and swim happy!