NitroCure™ vs. KoiCure™ vs. KanaRx™: Which Aqua Meds Antibiotic Should I Use?

Shop these Aqua Meds antibiotics: NitroCure™ | KoiCure™ | KanaRx™

Aqua Meds offers three pure, single-ingredient antibiotic products for koi and pond fish:

• NitroCure™ – pure nitrofurazone
• KoiCure™ – pure oxolinic acid
• KanaRx™ – pure kanamycin sulfate

All three help with bacterial infections, but they are not interchangeable. Each one has situations where it is the best choice. This guide is designed to help you understand the differences and choose the right tool for your fish and your pond.

At a Glance: How They Differ

NitroCure™ – External First-Line Treatment

• Pure nitrofurazone
• Best for common external bacterial infections
• Ideal for ulcers, fin rot, tail rot, and gill disease
• Multiple application options: dip, short-term bath, long-term bath
• Excellent first choice for many external problems

KoiCure™ – Strong Immersion Treatment for Tough External and Gram-Negative Issues

• Pure oxolinic acid
• Strong focus on many gram-negative bacteria (Aeromonas, Pseudomonas, and others)
• Used as a controlled immersion or pond-wide treatment
• Good step up when infections are more serious, persistent, or septicemia-like

KanaRx™ – Deep/Systemic Antibiotic and Medicated Food Option

• Pure kanamycin sulfate
• Broad-spectrum activity against many gram-negative and gram-positive bacteria
• Can be used as a bath, pond immersion, or medicated food
• Best reserved for severe, resistant, or systemic infections and situations where internal antibiotic action is needed

What Exactly Are NitroCure, KoiCure, and KanaRx?

NitroCure™ (Nitrofurazone)

NitroCure is a pure nitrofurazone powder formulated for use as a dip or bath treatment. It is aimed primarily at external bacterial infections, such as:

• Skin ulcers and erosions
• Fin rot and tail rot
• Many cases of bacterial gill disease

NitroCure’s strength is its flexibility: you can use higher concentrations for short dips or lower concentrations for longer baths, depending on the situation and sensitivity of the fish.

KoiCure™ (Oxolinic Acid)

KoiCure is pure oxolinic acid, an antibiotic with strong activity against many gram-negative bacteria commonly blamed for serious koi infections, including Aeromonas and Pseudomonas.

It is used as a controlled immersion treatment (and can also be mixed into food in some protocols). KoiCure is especially useful when:

• Infections look more serious than a simple small ulcer
• You see signs of septicemia (red streaking in fins or body, bloody patches)
• External infections are spreading or not responding to first-line approaches

KanaRx™ (Kanamycin Sulfate)

KanaRx is pure kanamycin sulfate, a broad-spectrum, deep-penetrating antibiotic. It can be used as a therapeutic bath, as a pond-wide immersion treatment, or as medicated food.

KanaRx is typically reserved for stubborn, advanced, or systemic infections, especially when earlier treatments (such as NitroCure or KoiCure) have not done the job or when symptoms suggest the infection has spread internally.

Which One Should I Start With for Ulcers?

For most koi keepers, the best approach is to start with a strong external treatment and good water quality.

Start with NitroCure™ if:

• You are seeing “typical” external ulcers or bacterial sores
• The fish are still active and eating
• The problem appears to be mainly on the skin, fins, or gills

NitroCure is an excellent first-line bath treatment for many external bacterial infections.

Consider KoiCure™ if:

• Ulcers are severe, deep, or spreading
• You see red streaks in fins or body, or a “septicemia” appearance
• A previous external treatment (including NitroCure) did not fully clear the infection

KoiCure gives you a different antibiotic class with strong gram-negative coverage and works well in controlled immersion treatments.

Reserve KanaRx™ if:

• The fish are showing signs of internal infection (dropsy or swelling, bulging eyes, extreme lethargy, chronic weight loss)
• Infections keep coming back or feel resistant to other treatments
• You need medicated food because the fish are eating and you want the antibiotic to work from the inside as well

KanaRx is your escalation tool when things are clearly more serious or internal.

What About Fin Rot and Tail Rot?

Fin rot and tail rot are extremely common and are often driven by stress and water quality issues, with bacteria taking advantage of weakened tissue.

In most cases:

• NitroCure is the best first choice for fin rot and tail rot. Its external bath action is well-suited to damaged fins and tails.

If fin rot is severe, spreading quickly, or not improving after a proper NitroCure course and water quality correction, then:

• KoiCure can be used as a follow-up immersion treatment when you need a different antibiotic class with strong gram-negative focus.
• KanaRx may be appropriate for advanced cases where you suspect internal involvement or where the fish show other systemic signs.

Regardless of which antibiotic you use, correcting underlying water quality problems (ammonia, nitrite, KH, crowding, filtration) is critical for lasting success.

How Are These Products Used? (Routes and Methods)

Always follow the label instructions for each product, but here is a general overview:

NitroCure™

• Dip treatment – short, higher-strength exposure (typically minutes), used when you want a concentrated external hit on ulcers or fin rot.
• Short-term bath – several hours at a moderate concentration.
• Long-term bath – continuous, lower-dose exposure in a hospital tank or treatment pond.

KoiCure™

• Immersion/Bath – controlled bath or pond treatment at a specific oxolinic acid concentration, usually over a defined number of days.
• In some protocols, it can be incorporated into feed (follow label guidance when available, or work with a koi health professional).

KanaRx™

• Therapeutic bath – short-term higher concentrations for more intense external/systemic exposure.
• Pond immersion – full-pond treatment at a lower concentration, with careful attention to biofilter and water quality.
• Medicated food – mixed into food to deliver the antibiotic directly through the gut to internal organs. This is often the most important route for suspected internal infections.

Can I Use More Than One of These Antibiotics at the Same Time?

No. We do not recommend mixing NitroCure, KoiCure, and/or KanaRx together in the same treatment or using multiple antibiotics at full strength at the same time.

However, they can be used sequentially, for example:

1. Begin with NitroCure for a straightforward external infection.
2. If the response is incomplete or the infection appears more serious or gram-negative in nature, move to a KoiCure immersion course.
3. If the infection is severe, persistent, or clearly internal, consider a KanaRx protocol (bath and/or medicated food), following label directions.

Stacking multiple antibiotics at once can stress the fish, damage the biofilter, and make it harder to know what is helping and what is causing side effects.

How Do These Products Fit into a Complete Treatment Plan?

Even the best antibiotic will struggle if the environment is working against the fish. A complete Aqua Meds approach usually includes:

Excellent water quality

• Use Aqua Meds water conditioners to remove chlorine and chloramine and detoxify ammonia and other toxins.
• Maintain proper KH and pH using buffering products.
• Keep ammonia and nitrite at zero and nitrate as low as practical.

Strong biological support

• Use beneficial bacteria products appropriate to your season to support filtration and reduce waste buildup.
• Keep filters clean and well-aerated.

Direct wound care when needed

• For significant ulcers or physical damage, consider a hands-on wound protocol using Aqua Meds wound care products, such as carefully cleaning the area, applying a dry antibiotic powder if appropriate, and sealing with a waterproof ointment following directions.

Targeted parasite control (if necessary)

• If parasites are involved, such as flukes, lice, or anchor worm, use the appropriate Aqua Meds parasite treatment before or between antibiotic rounds as recommended.

Using the right antibiotic at the right time, combined with good water quality and wound care, usually produces much better results than simply throwing more medications at the pond.

Quick Decision Guide

Here is a simple way to think about these three products:

Choose NitroCure™ if:

• You are dealing with new or typical external bacterial infections (ulcers, fin rot, tail rot, gill disease).
• The infection seems localized to the skin, fins, or gills.
• You want a strong, first-line bath treatment with dip, short-term, and long-term options.

Choose KoiCure™ if:

• External infections are more serious, extensive, or persistent.
• You see signs suggestive of septicemia or gram-negative bacteria (red streaks in fins or body, bloody patches).
• Previous first-line treatment (including NitroCure) has not fully resolved the problem.
• You want a different immersion antibiotic class with strong gram-negative activity.

Choose KanaRx™ if:

• You are dealing with severe, advanced, or resistant infections.
• You suspect internal or systemic infection (dropsy, swelling, exophthalmia, chronic wasting, and similar signs).
• Earlier treatments with NitroCure or KoiCure have not worked as expected.
• You need to use medicated food to deliver antibiotic from the inside as well as via the gills.

Still Not Sure Which Antibiotic to Use?

As a simple rule of thumb:

• For new, straightforward, clearly external infections, start with NitroCure™.
• For stubborn or more serious external infections, move to KoiCure™.
• For severe, resistant, or clearly internal infections, or when you need medicated food, KanaRx™ is often the best choice.

If you are unsure, please consult a koi health professional or contact Aqua Meds for guidance before beginning treatment.

Important Safety Note: All Aqua Meds antibiotic products are for ornamental fish only. Not for use on fish intended for human consumption. Always follow label instructions carefully and maintain excellent water quality during any treatment.