Effect of API Melafix on Pencilfish

[macdaddy36]

Yesterday I posted in my journal about this and I want to add more details and spread a warning about the API product melafix. 

What I did: My Apisto nipped my Gouramis and Guppies fins. I moved the apisto to a different tank. I added a standard dose of Melafix to the tank to try and stop infection/help the fins heal quicker. I then walked away from the tank for 30 minutes. Nothing else was added to the tank. pH 8.0, soft water, medium buffer, 5 nitrates, 0 chlorine 0 ammonia 0 nitrite.

What happened: My cousin walked by the tank and screamed "your fish are dead". I went back to the tank and 4 of the 7 pencilfish were already dead lying on the bottom. My cousin removed the remaining pencilfish to the other tank (he has fish too) while I did a big water change and tested the water. 2 of the pencilfish in the other tank were fine while the last one struggled for around 2 hours but eventually sank like the rest and died. 

All of the stuff below applies to air breathers as well as pencilfish. Apparently Tea Tree Oil is similar to turpentine (a liver toxin)

I read that the Tea Tree Oil in melafix reacts with soft water in some way to harm pencil fish and air breathers. This would make sense because although I have a high midwestern pH, we have a water softener so my water is very soft with medium buffer and a pH around 8.0. I mostly keep all soft water fish other than the guppies, so its never been a problem in the past. I also read that it has a larger effect on male pencilfish, which could explain why my two most dull colored pencilfish were completely fine while the rest sunk and died.

According to what I read, "if you are using this product with Bettas (and Pencilfish) , make sure that your KH is above 50 ppm, your GH is above 150 ppm, & pH is above 6.5 (or better above 7), and you should not have a problem.

 is that since the best research shows similarities between TTO and Turpentine (both are terpenes), is that in an acidic environment, in particular an environment with nitric acid or other acids as a result of organic decomposition such as carbonic acid, the chemical reaction can produce chemicals that may harm the liver in certain fish that have a tendency to ingest the water around them such as Labyrinth fish/Pencil fish (via the surface).

From https://www.fish-as-pets.com/2008/12/melafix-dangers-labyrinth-fish.html

Apparently API has done testing in the past because they have received lots of complaints off people having similar experiences to mine.. They report that Melafix is safe for all fish but one quick google search 'melafix pencilfish' shows this not to be true in every case. I emailed API about this to see if they could give me a refund for the melafix but that's unlikely as it's been a full day and I have not gotten a response so idk. I feel really bad because one quick google search and 5 deaths could have been avoided.

I will report that the Melafix does not effect the Gourami in the tank. I used melafix because that was what I had on hand and I have live plants in all my tanks so salt is not an option. In the future I definitely will order and use maracyn.

Edited December 11, 2023 by macdaddy36
adding on

[Fish Folk]

Thank you for the PSA. Sorry for your fish loss. I've used M-fix in the past without a problem, and my water is very soft from the tap -- below 50 ppm. I eventually stopped using it for other reasons. Fish can typically heal fine on their own if their environment is kept clean, chemically stable and stress-free.

[macdaddy36]

On 12/11/2023 at 2:18 PM, Fish Folk said:

Thank you for the PSA. Sorry for your fish loss. I've used M-fix in the past without a problem, and my water is very soft from the tap -- below 50 ppm. I eventually stopped using it for other reasons. Fish can typically heal fine on their own if their environment is kept clean, chemically stable and stress-free.

I agree with keeping clean water is most important. I figured adding it couldn't hurt, but I was obviously wrong.