Salt is the greatest bath treatment of all time. This would have to be one of the single, uncontested assertions made in this website. Salt is both tonic to fish and toxic to parasite. It’s got a wide spectrum encompassing most of the ciliated protozoans and it can offset the negative effects of some water quality derangements such as Nitrite accumulation.
Salt can occur in numerous forms. The first salt I ever used was from the pet shop and cost quite a bit. It worked very well. It must have been very special. Perhaps distilled from the tears of Hawaiian orphans.
Many folks have used Kosher Salt, Water Softener salts, “Solar” salt, rock salt, Sea Salt, Ice Cream Salt, Synthetic Reef Salt (Instant Ocean®) Non-mineralized Salt blocks for cows, and table salt. Results with all of these have been excellent with the following notes: Sea Salt is rich in carbonates and will raise Total Alkalinity and pH which may be undesirable if there is a significant Ammonia accumulation or your fish are adapted to an acidic pH. Cow Salt Blocks occur in a mineralized format, rich in Magnesium and other minerals. You’ll kill your fish unless the salt lick is 99.9% pure salt without trace minerals. Make sure the label indicates the salt is not trace mineralized and that the salt is 99.97% NaCl.
No salt should contain Yellow Prussiate of Soda, or YPS. Another anti-caking agent contains cyanuric acid. Avoid this as well. The salt should contain no Iodine because while this will have no negative effect on the fish, it may damage beneficial bacteria.
Why is Iodine bad? Well, a hundred years ago when I first started using salt, I’d add it “all at once” and that caused osmotic ‘shock’ to the nitrifying bacteria and we’d see a pulse in nitrogen. I assumed it was the Iodine. That’s what I published. That misinformation’s hanging around to this day. My bad. Sorry.
Why is Yellow Prussiate of Soda “Bad?” Well, I didn’t know where that got started. I just read that. And a LOT of the time, the YPS didn’t matter so I started to think, “Ehhh who cares?” but then something happened up in Tennessee that made me consult a chemist. A mess of fish got sicker and sicker with YPS salt being used. Why?
It turns out that YPS (Yellow Prussiate of Soda) turns into “Prussic Acid” in water. And normally that gets neutralized by carbonates in the water. But if there aren’t enough carbonates, the pH becomes acidic and can hurt the fish. So what I learned was: In hard water, YPS Salt is fine. In soft, low carbonate rich water, YPS can burn the fish. Or crash the pH.
On the other hand, the desiccant Sodium Alumino-silicate is just fine.
Salt Dosing Journal for Ich or White Spot
Indications for the use of salt include the elimination of parasitisms caused by vulnerable ciliated protozoan parasites, curbing the absorption of Nitrite, and reducing the osmotic pressure exerted by fresh water on any hole in the skin or gill.
Salt also makes popcorn taste great, and it melts the snow on your driveway in winter.
Dosing salt is usually simple.
The dose for 0.3% solutions is 1 tablespoon per gallon. This is the amount used for most protozoan parasitisms
The dose for 0.6% solutions is 2 tablespoons per gallon. This is the dose for salt resistant Trichodina and Costia. Dosing variations exist based on live plants, volume of the water, what parasite is targeted and what species of fish are involved.
The dose for 0.9% solutions (common in German texts) is 3 tablespoons per gallon.
First, you must remove any live plants of value from the aquarium.
- Perform a significant percentage water change before starting, because you will want to avoid water changes if possible after salting in order to maintain a stable concentration.
- At the zero hour” add one third of the total dose after pre-dissolving it in a small bucket of water.
- Wait twelve hours while the fish acclimate.
- Then apply the second ‘third’ of the salt dose, after pre-dissolving it.
- Twelve hours after that, you’ll apply the last ‘third’ of the total dose. The whole amount has been added over twenty four hours, and there will be nominal effect on the fish or filter.
Let’s work as example to keep folks out of trouble:
This fellow, whose name is Vino DePascagliatelli (he’s fictitious but the name is fun to say fast) has a fifty-five gallon fish tank full of fine Chinese Ranchu. (He never went for those big ugly-headed Orandas). Anyway, his fish break with Ich because he bought a new fish from an otherwise reputable dealer and did not quarantine it. The Ich is obvious because the fish have white spots all over their fins and bodies. So he checks out this book and quickly figures up his total dose of salt.
0.3% represents one tablespoon per gallon.
He has a fifty-five gallon tank and the fish are stable, so he figures the dose into “thirds” for gradual addition. That would be 18.3 tablespoons every twelve hours.
It’s ten o’clock by the time he gets home with the salt. He bought So-Lo® brand rock salt with Yellow Prussiate of Soda. He’s just about to burn his fish when his wife notices it: “Vino, Vino!! Oh my Gawd, Vino lookit he-ah! Lookie! Doc Johnsin’s book says not ta’ use no salt wit Yella’ Prussiate uh Soda in it!”
Vino grabs his receipt and runs down to the local mart, and exchanges the salt for Dandy® brand, which has Sodium Alumino-silicate as its anti-caking agent. This is fine.
He gets home just in time to meet his wife at the door. She’s going to get lunch with her friend Maria, and she still has curlers still in her hair.
He checks his watch. It’s noon. Vino adds 18 tablespoons of salt. When it dissolves it leaves a little sand on the glass bottom of his tank. No big deal.
“Docta Johnson din’t say nuttin’ ’bout no sand bein’ left behind in da tank”. He’s a little miffed but he ignores it, as he should.
Twelve hours later, at midnight, his wife wakes him up.
“Dincha’ hafta add some mowa salt ta ‘dat fish tank ovah daya?”
“Jeez Stella, ‘tanks fer wakin’ me up, I almast fa-got!” Vino rubs his eyes and applies another 18 tablespoons of salt to the tank. He goes back to bed. Stella still has the curlers in her hair.
It’s noon the next day when Vino walks over to the tank. (Well, Vino kind of struts like a large chicken, and he has a gigantic pompadour, but that’s another story). He leans down and notices the fish are perkier. The spots are still there, but he’s a trusting fellow. So he adds his last eighteen tablespoons and sits down to read the paper.
That night, Stella is counting all the white spots.
“One thousand eight hunnid and ninety seven! Vino! They’re goin’ away! Yestaday dare wuz two ‘tousand five hunnid and toidy!”
Vino puts his head in his hands. She starts counting the white spots all over again.
Forty eight hours later, she is counting the white spots again. She still has curlers in her hair.
“Jeez, Stella, are we gonna go to some kinda big Poddy at da end ah da munt? Whatcha wearin’ ‘dem ‘coilas fa?”
“Oh shut up, Vino!” she retorts. “I shou’nt tell ya dis, ’cause yer bein’ such a goombah, but, doze Ick bugs is all gone away!”
Vino jumps up and looks. Within about 72 hours after the last salt dose, at seventy-four degrees oF all of the Ich cysts have vanished from the skin. He leaves the salt in for ten more days just to be on the safe side. Later that week he wins the New York Lotto and sends Dr. Johnson a new Lincoln Town Car for all his careful advice in this great book.
If the fish are dying off quickly, it is advisable to add the salt dose all at once. This may have a negative impact on filter bacteria but may be life saving in the case of Chilodonella, Costia or even Ich in smaller fishes.
Is it possible to apply too much salt?
Well, it would be hard to do since Koi, goldfish and pond fish can handle high salinity. They will survive salt levels up to 0.9% and higher. However, this should be recognized as a stressful salt level and only used when absolutely necessary. Small, weak fish would do their best at 0.3% with observation. “Not Worse” is a good result. If the fish are ‘hanging in there’ after a day or two, then you can climb to 0.6% without losses.
This is a Koi, goldfish and pond fish health book but many people keep tropical fish with their Koi, goldfish and pond fish. Several species of catfish are negatively affected by salt. Er, well, that means they may stop breathing, severe stiffness results and they are not as entertaining to watch anymore. Examples of these fish would be wild caught Brokis britskii catfish, some wild caught Corydoras species, Rafael cats, Ramirez cichlids, and Rasboras. There are other sensitive tropical barbs, so any fish you are not sure of should be removed before treatment.