Melafix Review and Research

Melafix is quite a popular medication in the aquarium hobby, by the company API. Chances are most people have at least heard about it. However, there is remarkably little information on this medication online, and whatever information is scattered and not centralized.

API MELAFIX Fish remedy For Bacterial Infection in Freshwater Aquarium 16-Ounce Bottle

What is Melafix and what is Melafix’s ingredient?

The active ingredient in Melafix is Melaleuca oil at 1.0% concentration. We can easily then see how Melafix got its name. Melaleuca oil comes from the a tree in the Melaleuca genus, which includes the popular “tea tree” from which “tea tree oil” is derived. Note that there is a technicality where “contrary to popular opinion it is not made from the common Tea treeMelaleuca alternifolia, but from Melaleuca leucadendra, also known as the Cajeput Tree” (Wikipedia).

Melafix Research

There seems to be not much research done on Melafix. One of the few research papers is the following:

The use of Melafix on goldfish and clownfish appears to be safe as no adverse effects were noted during the experimental period. The results also showed that Melafix has no effect on the water-quality parameters tested. In vitro efficacy studies were conducted by determining the minimum inhibitory concentration and minimum bactericidal concentration of Melafix on various pathogens. The study revealed that Melafix had no significant bactericidal or inhibitory effect on any of the pathogens tested. This observation suggests that anecdotal benefits of Melafix are not owing to antibacterial activity.


The above paper seems to show negative results (no antibacterial activity of Melafix), but at least there is no harmful effects on the fish nor water parameters. The effect of Melafix may not be due to the antibacterial activity per se, but possibly the healing and regenerative aspects of it, or boosting the fish’s immune system and regrowth of tissue.

A paper showing positive effects of Melafix is the following:

In particular, a combination treatment of Melafix® and Pimafix® was highly effective at reducing in vitro survival of parasites from 15 to 2 h and eradicating 95% of gyrodactylids in vivo. The unexpected high efficacy of this combination treatment is likely explained by the high content of terpenes and phenol propanoids in the cajuput and West Indian bay oils, as well as the anti-helminthic properties of the emulsifier Crovol PK 70. Hence, Melafix® and Pimafix® effectively reduce gyrodactylid burdens on fish, increasing the chances of efficient disease control in ornamental fish.


Yet another paper is not on Melafix, but on its active constituent Cajeput oil:

Main antibacterially active agents obtained from plants-Cajeput essential oil–1,8 cineol, linalool, alpha-terpineol and terpinen-4-ol, for example from Melalleuce leucadendron (Myrtaceae) as well as essential oil from Ocimum gratissimum (Labiatae) were combined in tests in vitro with selected antibiotics. Above mentioned plant products were found to be effective medicaments for local application in modern medical practice. Combinations with antibiotics potentiated their therapeutical action. On the basis of tests in vitro the synergistic action of these two kinds of medicaments, i.e., preparations traditionally used for a few last decades–antibiotics–might be well applied for therapeutical needs.


Hence, the above link supports the view that Cajeput oil (active ingredient of Melafix) does have antibacterial properties!

Anecdotal Evidence of Melafix

Judging by Amazon reviews (, many people do claim that Melafix works in curing their fish of fin rot, popeye, and various other ailments.

The biggest advantages of Melafix are as follows:

  • Does not kill beneficial filter bacteria
  • Does not stain water (colorless)
  • Shrimp safe
  • Snail safe
  • Plant safe
  • All natural

The most “powerful” medication is of course fish antibiotics, but that is the last resort as there are many side effects of antibiotics, including possible wiping out all filter bacteria, and development of resistant bacteria.

An example of fish antibiotics is API General Cure, which is a very powerful fish medication that can treat very serious diseases such as “hole in the head”.

API GENERAL CURE Freshwater and Saltwater Fish Powder Medication 10-Count Box

Melafix Reviews

The below is an amazing case of recovery from popeye (eye dangling out) treated by Melafix.

It was absolutely the worst case of Popeye I have ever see with the eye protruding almost 3/8 of an inch and hanging down.. It was so nasty looking that the wife & kids wouldn’t go near the tank as the sight made them feel sick.. I was nearly to the point of putting it down as I figured it would surely get worse and if there was some type of infection involved, I didn’t want to contaminate the tank.

I decided to treat the tank with a product made by API called Melafix. This is an antibacterial made from the extract of Tea Trees. I only used 1/2 the recommended dose as to not create any major impact to the rest of my tank and system.

Long story short, within 2 days of the treatment I thought I noticed a change and saw the fish actually eat. I treated the tank again after 3 days and the eye definitely improved.. After the second treatment I just watch with amazement as the fish made a complete recovery within two week with no sign what so ever the initial problem.



Author: mathtuition88

Math and Education Blog

One thought on “Melafix Review and Research”

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