Active ingredient: Seachem MetroPlex: metronidazole 70% (excipients 30%). API General Cure: metronidazole 1-10% + praziquantel 1-5% in sodium chloride
How to use (from the label): MetroPlex can be dosed in water (1-2 measures per 40 L every 48 h for up to 3 weeks; remove invertebrates, carbon/Purigen, turn off UV) or fed daily as a medicated food made with Seachem Focus binder (up to 3 weeks); Seachem says it works for internal and external infections either way and calls food mixing 'well suited' for internal parasites.
Careful: Follow the label. Seachem says MetroPlex can be combined with KanaPlex (in food with Focus); remove invertebrates when dosing in water (food mixing is Seachem's option for tanks with invertebrates); 'little danger of overdose'. Metronidazole carries a California Prop 65 cancer warning (API General Cure): avoid handling exposure.
Rules: Nitroimidazoles (metronidazole's drug family) are prohibited for extralabel use in food-producing animals in the US; Seachem labels MetroPlex for ornamental fish only.
Never mix medicines unless the label says it is safe, and remove shrimp and snails unless the label says they are safe.
Examples you may see in shops: Seachem MetroPlex, API General Cure. Not endorsements. Always follow the label.
6 facts checked with sources