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Maracyn's active ingredient is Erythromycin. The savings come in the large 24 pack or larger over the traditional API Erythromycin. Each packet treats 10 gallons.

Provides relief from bacterial infections such as body fungus, gill disease, fin rot and popeye in fresh and saltwater aquariums.

Mardel 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.

All suspected bacterial infections should be treated immediately.

Mardel Maracyn® is non-toxic to invertebrates such as snails and shrimp. 

Don't confuse this with Maracyn 2, which isn't the same we don't currently carry.

Mardel Maracyn

Frequently bought together

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Maracyn's active ingredient is Erythromycin. The savings come in the large 24 pack or larger over the traditional API Erythromycin. Each packet treats 10 gallons.

Provides relief from bacterial infections such as body fungus, gill disease, fin rot and popeye in fresh and saltwater aquariums.

Mardel 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.

All suspected bacterial infections should be treated immediately.

Mardel Maracyn® is non-toxic to invertebrates such as snails and shrimp. 

Don't confuse this with Maracyn 2, which isn't the same we don't currently carry.

Customer Reviews

Based on 40 reviews
95%
(38)
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3%
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T
T.C.

A must have with the Med trio! Works best with a 10gallon quarantine tank.

R
R.Z.

Always have this on hand. Treat all new fish and an occasional issue if it arises.

B
B.R.
Worked as expected!

Have used this during QT as part of the Coops med trio recommendation. Has taken care of early outbreaks of both cotton mouth and popeye during the QT period of some of my newly purchased fish over the last year. Would recommend any aquarist always have a box of this standing by in your fish supplies.

C
C.B.
Long time useful product

Use this as part of the trio for new fish and also for occasional problems. One of the best meds I have found.

S
S.W.
super quick delivery

got here 3 day after i ordered and on the day before Thanksgiving . i haven't used it yet , just like to have it on hand.