Treats bacterial infections
Safe for aquarium plants
Safe for shrimp, snails, and other invertebrates

Fritz Maracyn® is a specially compounded broad-spectrum antibiotic (erythromycin) which has been shown to be effective against a number of pathogenic bacteria associated with ornamental fish disease. It was developed for complete but gradual dissolution in water. It is primarily effective against gram-positive pathogenic organisms. Symptoms of clamped fins, swollen eyes, heavy or rapid breathing, patchy coloration, change in swimming behavior or corner-hiding can be signs of possible bacterial infection.

For the 10-count and 20-count boxes of Maracyn, the medication comes in individual packets where each packet treats 10 gallons of water. The 100-gram bulk container treats a total of 1,000 gallons of water while the 400-gram bulk container treats 4,700 gallons of water, and both containers come with a scoop for easy dosing. When treating with Maracyn, we recommend using an air stone in the aquarium, which may temporarily cause excessive foaming at the water surface.

For best results, we recommend removing chemical filtration from your aquarium filter before dosing the medication. Examples of chemical filtration include activated carbon, carbon-infused media pads, Seachem Purigen, phosphate media pads, and ammonia media pads.

Manufacturer's Directions on the Package:
One complete course of treatment will take 5 days. Treat for the full course of treatment even if visible signs of infection or illness disappear.
— Day One through Day Five: Each day, add contents of one packet per 10 gallons of water to be treated. For the bulk jar, add 1 level scoop (approximately 1 gram) per 10 gallons of water each day.
— Day Six: Perform a 25% water change. If necessary, a second full course of treatment may be performed starting on Day Seven.

Aquarium Co-Op Instructions:
Dose one packet (or 1 level scoop from the bulk jar) per 10 gallons of water to be treated. Let sit in aquarium for 7 days. Then do 25% water change.

Notes:
— All suspected bacterial infections should be treated immediately.
— Fritz Maracyn® is non-toxic to invertebrates such as snails and shrimp.
— Don't confuse this medication with Maracyn 2, which is not the same medication and is not a product we currently carry.