View Full Version : Potassium Chromate In Veternary Use As An Antifungal Question.

2018-Aug-17, 06:44 AM
I've been wanting to ask this one for a while now.

When I was a professional aquarist one issue I saw about three or four times a year, usually in pond goldfish after cold weather, was a rather unpleasant fungal infection that produced a thick mat of blue-grey mold on the poor fish. Thick and nasty, you couldn't pull this stuff off with forceps without tearing the fish apart.

I had even developed an eye for survivability based on the medications available for me to use.

For years I was ignorant the grades of antibiotics within a class of antibiotics, like tetracycline for instance.

You have human grade tetracycline, veterinarian grade tetracycline and then the stuff the janitor sweeps off the floor while *thinking* about antibiotics, AKA aquarium grade tetracycline.

So with nothing but aquarium grade antibiotics at my disposal I really had to triage the charges under my care, though I didn't call it that at the time. After decades I just knew.

And then one day Jungle, a fish product company, introduced a potassium chromate antifungal.

The first time I used it on a suitably sick fish, one I thought was a goner, I wasn't just stunned, I was flabbergasted! As I *watched* the layer of mold simply peeled off the fish. And after the damaged tissue recovered the fish went home a week later.

Can anyone explain why the hyphae dissolved so suddenly?

2018-Aug-17, 07:09 AM
My mistake.

Potassium dichromate, if it makes a difference.

2018-Aug-17, 12:42 PM
I don't have the answer BD. I'm not surprised the antibiotics didn't do anything for a fungus infection.

But apparently, there is a patent (https://patents.google.com/patent/US4331660A/en) on using the chromates for fungus on fish eggs.

Be careful with the chromates, the hexachromates are carcinogens (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1568823/).

2018-Aug-19, 10:55 PM
Potassium dichromate is a strong oxidizer. It will turn alcohols into carboxylic acids, even near neutral pH.
The fungal mat on your fish is likely a complex carbohydrate, so dichromate will chop it to pieces.
The trick to using it on fish fungus is likely to get the concentration low enough so as to not kill fish, but high enough to do chemistry on the stuff coating the fish.
You break a long chain Polysacharide (https://en.wikipedia.org/wiki/Polysaccharide) in the middle a few times, and its resulting bits become more water soluble fast. Since that goo layer is what's holding the fubgus to the fish, results should be quick.
The stuff is carcinogenic, so we people have to go with wimpier measures on ourselves.
In addition to being an antifungal, it used to be quite common to mix potassium dichromate with concentrated sulfuric acid to clean glassware in chem labs.
Likely illegal now, as chromium salts are nasty things to dump down sinks.
The dichromate is also interesting in that it can dissolve the oxide (sapphire) layer on powdered aluminum. That makes it useful in making fireworks containing aluminum.