Fish Zole Metronidazole Dosage:250 mg Safe for long term use to Safe for long term use to support gut balance and overall health sensitive to traditional medications and suitable for long term use naturally occurring probiotics for active digestive support gram negative organisms & protozoan parasites Tank Compatibility Freshwater & saltwater ornamental fish Prescription Required No Grade USP Pharmaceutical Expiration Typically 1–3 years from manufacture date Product descriptions and usage instructions shown here are taken directly from the manufacturer’s product label and information provided by Montana Aquarium Supply