API General Cure API General Cure is a powder medication that treats a wide variety of parasitic diseases in fish — including internal and external parasites such as flukes, Hexamita ("hole-in-the-head"), velvet, and more. Built around metronidazole and praziquantel, it's a versatile broad-parasite treatment and a popular component of new-fish quarantine, supplied in pre-measured packets. Good to Know: Because it pairs two complementary anti-parasitics, General Cure covers both the worm/fluke parasites (praziquantel) and protozoan/internal parasites (metronidazole) — which is why many keepers use it prophylactically when quarantining new arrivals. It won't treat bacterial or fungal infections, so match it to parasitic symptoms (flashing, scratching, white stringy feces, hole-in-the-head). A Caution for Inverts: Keep it away from shrimp and snails, treat in a quarantine tank where possible, and remove carbon while dosing. Dosing Guidelines: Dose per the label using the pre-measured packets, with a second dose after 48 hours and a water change as directed. Complete the full course; for internal parasites, medicating food can help.