Technically, this is an antibiotic, but most use it against flagellates, like hexamita.
Manufacturer recommends dosing at 1/4 tsp per 40 gallons, though most aquarium guides are now recommending 1/4 tsp per 20 gallons.Re-treat every 24 hours for 10 days. Do a minimum 25% water change before each retreatment. Metro is effective against some anaerobic gram positive bacteria. When combined with Neomycin Sulfate, it works well for bloating of the digestive tract. Its most common use is for flagellates, but when combined with other meds, it can make for a more potent agent against many internal parasites.For ornamental fish use only.