Melafix warning - Dead Pencilfish

[Riz1]

Hi All,

I've just had the most horrible experience with Melafix.

I treated my 280 litre tank with 30ml yesterday to help my corys that are loosing barbels.

I posted about this earlier and did a water test 6 days before using Melafix with the following results.

GH: 12
KH: Between 3 and 4
PH: 7.6
High range PH: 7.8
Ammonia: 0.25 ppm
Nitrite: 0 ppm
Nitrate: 5 ppm

I had 6 perfectly healthy and breeding Golden Pencilfish. The 2 males had coloured up nicely and often sparred with each other. I was not breeding them on purpose but often saw them in action and scattering eggs amongst the floating plants.

Less than 30 minutes after the treatment, 2 males were dead. It was sudden. They started swimming upside down and eventually floated to the bottom dead.

Weirdly enough, my female pencilfish remained perfectly fine. Now I imagine them being female because they are more lightly coloured and did not spar like the 2 darker coloured dead ones. Unless they are another sub species that were sold to me mislabelled and perhaps Melafix does not effect them.

I did my research on Melafix before using it and found it to be safe for all fish types. However, when I search Google again with the keyword 'pencilfish' I see many posts with other hobbyists having the same experience.

Apparently API have done further research on this but found Melafix to have no ill effects on Pencilfish. As such, they have opted not to post a warning label on the product.

I'm not sure whats going on. Perhaps it only effects a particular species of pencilfish or maybe only males that are actively breeding?

In any case, hope someone sees this and I manage to save them from making the same mistake.

 

[fishingBuds]

I'm using melafix for 4 days now and my fish ich is disappearing, nothing died..

I did not tested the water yet, and I did not take the carbon activated system.

I simply took the CO2 system off and I'm not adding anything else (I was dosing my tank with seachem plant pack). The fish still hungry, ich is disappearing and no deaths at the moment (i dosed yesterday 1/2 more dose into the tank and didn't seem to change the behavior of my German Blue Ramirezi, Neon Tetras and Dojo loach)

I heard a guy on youtube saying that goldfish species are more sensitive to medications...

I've heard also people saying to take the whole filter out, thats not right, this medications decrease the O2 dissolution in water and without the filtration surface movement, the O2 in the water goes down making your fish die from other type of issues.

Thats my experience with melafix for 4 days in my 20g planted tank.

 

[Riz1]

Hi Finishingbuds. Glad to hear you've had a better experience. However, Melafix appears only to be fatal to some Pencilfish. Other species seems fine with it.

I did some further research but can't be sure if its to do with a mix of water chemistry and Pencilfish or if its a specific Pencilfish species that its fatal to.

I managed to find some old pictures of my fish.

Maybe someone can help identify them here. The darker colored ones died. The lighter colored Pencilfish were not effected by this medication.

I had assumed the darker ones to be male but maybe they are a different subspecies.

 

[fishingBuds]

Usually, the males are pretty much paler that the females and the other difference between them is the white blotch at their bottom dorsal fin. When they procreate, the males’ whole body becomes a lot brighter.
The difference between males and females can also be noticed by their behavior where the females are more obedient than the males.

 

[Riz1]

Ignore the identification request on the last post. Appears I had 2 more males and they have now turned the darker color after missing the dead ones and have started sparing. Less competition I assume.

They are surely the same species. Unsure why only the 2 colored ones were effected by Melafix and the other fish got through it.

I'm starting to think if these surface dwellers are exposed to a high concentration of Melafix which effects them because they tend to chase any activity on the surface. Maybe they got a really high dose when medication is poured in.

I have seen some posts regarding Bettas suddenly dying of Melafix as well.

Will not test it again on my Pencilfish though.

Although I hope API take notice and put warning up. Considering it kills healthy Pencilfish in under 30 minutes.

 

[fishingBuds]

Hahahahaha, sometimes your fish think its food and accidently is granted a full meal of chemicals...
Thats something I dont like to do with my fish when medicating, they are always hungry when I get closer to the aquarium, thats a good sign, so I pretend I have the food to the left corner when I'm actually pouring the medicine in the right corner, where the most agitated area of the water surface is.
When nedicating, I dont like to do it close or at the feeding time, just in case their food could react with the high chemical change. I have to change the food style and I feed them differently, I check if the amount of food is good, good enough to nothing else goes to the bottom, then I feed the bottom feeders and the shrimps at their hidden spots. I'm taking out all possibilities of risk.

However, you want the medicine to react as soon as possible and cure your fish, so i would understand if pouring directly into the fish's face is actually not bad at all and has the same effect, anyway the medicine will be in your whole tank in matters of seconds if you keep the movement.

Looks like you have a pretty well planted tank, nice colorations