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Fritz Aquatics

Fritz Mardel Maracyn Oxy

Fritz Mardel Maracyn Oxy

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Regular price $12.99 USD
Regular price Sale price $12.99 USD
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Fritz Maracyn® Oxy is a quick and effective treatment for infections of true fungal infections on fish and eggs (whitish tufts of cotton-like material) and some bacterial diseases. It slowly releases small amounts of a stabilized oxygen-chlorine combination which, when used as directed, has an unusual ability to treat a wide variety of tropical fish diseases. Fungal infections are usually found at the site of an injury or recent attack from parasites. A true fungal infection has a cotton-like appearance similar to a mold found on fruit, bread or cheese, except that on fish, it is usually white instead of black or green. Fungal infections are very difficult to treat and are usually secondary invaders resulting from an injury on the fish or recent wounds from parasites or bacterial infection. Once the fungus starts growing on the fish, it usually continues to grow and enlarge. Unless medication is provided, death results. Fritz Maracyn® Oxy has also been shown to be effective against some gram-negative and gram-positive bacterial infections.


Fritz Maracyn® Oxy successfully controls true fungal infections caused by Saprolegnia, Ichthyosporidium, egg fungus and related species, and some common bacterial infections, such as fin and tail rot. Fritz Maracyn® Oxy can be used to treat fish exhibiting the following symptoms: clamped fins, swollen eyes, heavy or rapid breathing, patchy coloration or any change in behavior of the fish.


All suspected infections should be treated immediately.




Use 2.5 mL (1/2 capful) per 10 gallons of water. For smaller tanks, use 5 drops per gallon. Repeat daily as needed for up to 5 days.


Day 1: Add 2.5 mL per 10 gallons of water

Day 2: If symptoms persist, add 2.5 mL per 10 gallons of water

Day 3: If symptoms persist, add 2.5 mL per 10 gallons of water

Day 4: If symptoms persist, add 2.5 mL per 10 gallons of water

Day 5: If symptoms persist, add 2.5 mL per 10 gallons of water

Day 6: If symptoms are still present, a repeat course of treatment will not be effective. We recommend to try our Maracyn® and/or Maracyn® Two treatments.


For best results, use Maracyn® Oxy in a quarantine tank

Carbon does not need to be removed during treatment, maintain normal filtration, adequate water flow and aeration

Discontinue use of UV sterilizer during treatment

No contraindications: can be used with all of our other products and meds

Not suitable for use with starfish or related species; safe for use with other types of invertebrates

Do not perform water changes during the course of treatment. Maracyn® Oxy does not inhibit nitrifying bacteria, and will not impact the biofilter.

Overdosed? Neutralize the medication by using an aquarium dechlorinator, such as FritzGuard®, Fritz A.C.C.R. or Fritz Complete.


Note: FOR AQUARIUM USE ONLY. Consult a veterinarian or fish expert for assistance in diagnosis of disease causing organisms and treatment options. If you are unsure of the specific infection, Maracyn® Oxy may be used concurrently with Coppersafe®, Maracyn® or Maracyn® Two.


Fritz Maracyn® Oxy is not a toxic material but certain people may have a reaction. Use the following antidotes:


External antidote: Flood skin with plenty of water. If irritation persists, get medical attention.

For eyes: flood with plenty of water and call a physician immediately.

Internal antidote: Drink large quantities of milk. Call physician.

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