Fritz Aquatics Mardel Maracyn Water Treatment, 8 count

By Fritz Aquatics
Rated 2.4 out of 5 stars
$12.99Chewy Price
No Longer Available
This item may be discontinued. We're not sure when it will be available again.

About This Item


  • Created as a high-quality antibiotic.
  • Treats bacterial infections, including fungus, popeye, gill disease and more.
  • Use it in freshwater or saltwater environments.
  • Works quickly and effectively.
  • Easy to use and administer.

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Questions & Answers

5 Customer Questions

Does this contain erithromycin? What are the active ingredients?
Answer by ChewySep 04, 2022
The Active ingredient in this treatment is Erythromycin. Maracyn® is a specially compounded broad-spectrum antibiotic 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. Provides relief from bacterial infections such as body fungus, bacterial gill disease and popeye. Also helpful against mouth fungus, open lesions, hemorrhagic septicemia, and slime disease.

Is this ok to use with live plants?
Answer by ChewyJul 06, 2023
Some more sensitive plant species may display yellowing, but this condition generally improves after the treatment; remove any plants if concerned

will this help catfish with red gills and hazy eyes.
Answer by ChewyMar 24, 2023
This water treatment is designed to treat body fungus “columnaris”, fin and tail rot, and popeye and gill disease in freshwater and saltwater fish. This product is safe to use around invertebrates including shrimp and is ideal for tetras, cichlids, catfish, goldfish, angelfish, clownfish, damsels and more.

Is this product reef safe (corals)?
Answer by ChewySep 04, 2022
This treatment is safe for use in freshwater and saltwater aquariums. It is also safe for use with invertebrates.

ReviewsWrite a Review

Rated 2.4 out of 5 stars
5 Ratings
Would recommend to a friend

5 Customer Reviews

Rated 5 out of 5 stars
By BlueHoundie on Oct 7, 2023

Does its thing

It is what it's supposed to be, it does what it's supposed to do. Beware the powder while emptying the packets--it smells terrible and you'll taste it for hours. But that's not a flaw--it's simply the nature of the substance.

Rated 1 out of 5 stars
By Kathleen on Nov 19, 2023

Fritz Maracyn water treatment

Unfortunately this did not work for my fish. I followed the directions but it had no affect.

Rated 1 out of 5 stars
By Maracyn on Jul 2, 2023

Killed my fish

This product did not work and in fact killed all my fish. I used as instructions indicated and now all my fish are dead.

Rated 4 out of 5 stars
By Leticia on Apr 12, 2023

Mardel Maracyn

This product was purchased to help eliminate infection from a few fish in my tank which got popeye any body fungus.

Rated 1 out of 5 stars
By Dubs on Oct 1, 2022

Not helpful in my case.

Got this for a fish that lost an eye and a rubberlip pleco I received with fin rot. It did not help the fin rot whatsoever. It may have even progressed. Dosed according to directions. It’s possible my fish was infected with a gram negative bacteria as this only covers gram positive from what I’ve researched. Idk if it’s possible but I wish I could get a refund or replacement with Maracyn 2 as this is a bit more costly compared to other medications.