Using Aquarium Salt and Epsom Salt for Health Solutions

It is not uncommon for Betta fish to need some sort of medical treatment in their lives. Whether they suffer from tail biting or constipation, it is important to try to cure an ailment without medication if possible. Many common health problems start out as an issue that does not require medicinal remedies, which is good because unnecessary exposure to medicines can result in an immunity against them either from the fish or bacteria/parasite/virus you are trying to rid your fish of. Two fantastic tools to have in your arsenal of Betta fish healthcare items are aquarium salt and Epsom salt.

API aquarium salt is one of several popular options as a health care item for Betta fish owners. Photo by API

It is important not to substitute either of these salts with table salt or any salt that has been iodized, since iodized salts are deadly for Betta fish. It is equally important to make sure that your Epsom salt is unscented for similar reasons. Some popular aquarium salts include these from API brand, Jungle brand, and Pet Solutions. Many betta owners opt to use non-iodized that is not pet-specific, such as kosher salt, that they already have in their homes. Ultimately, rock salt and kosher salt are the same as aquarium salt and so long as there is no iodization or anti-caking elements added you should have the right stuff.

Anti-caking elements (sodium hexocyanoferrate) contain cyanide, and while cyanide is poisonous to fish at high levels of exposure it is not known how anti-caking agents effect fish at low levels for long exposure, so it is in your pet’s best interest to avoid it. If you choose to use salts that are not aquarium specific make sure they are safe for fish before use. It is equally important not to use aquarium salt and Epsom salt interchangeably. They are not the same thing and do not cure issues equally. Using the wrong type of salt to help your fish will have unyielding results and can do more harm than good. If you have issues that both types of salts may help with, it is recommended and explained later in this article that you should only use Epsom salt for treatment. Do not mix salts.

Aquarium Salt (sodium chloride)

Let’s first look at the benefits of using aquarium salt. Aquarium salt can be used to help reduce stress, prevent bacterial infection from open wounds such as torn fins, help with the recovery of fin loss, prevent nitrite damage to gills, and can be used to combat various diseases. Aquarium salt used to be recommended to use in every water change. This is no longer the case.

In an interview with the United Kingdom publication, Practical Fish Keeping Magazine, fish healthcare expert Dr. Peter Burgess stated, “Unless the species has a natural requirement for salt, then we should not add salt to an aquarium (or pond). Tonic salt for freshwater fish is a bit like aspirin for humans: both medicines have many beneficial uses, but neither should be administered routinely just for the sake of it.”

Stressed Betta splendens can benefit from appropriate uses of aquarium salt. Photo by A. Sivan of BettaSmart

Stressed Betta splendens can benefit from appropriate uses of aquarium salt. Photo by A. Sivan of BettaSmart

He continued on and explained, “Salt can be used as a supportive for salt-tolerant species, for example if the fish have severe ulcers or other major skin breaches that can place a burden on the osmoregulatory system. But healthy, unstressed fish do not need this support. Never use salt to compensate for bad fishkeeping!”

So why do people use aquarium salt? It is useful, as even Dr. Burgess points out later in the interview, for specific cases. Aquarium salt works in a few ways. It helps stress by helping fish maintain their osmoregulatory system. This means that fish who are stressed lose the healthy amounts of salt they have in their body through osmosis. This can create an unhealthy environment for the fish as the water is no longer balanced to support their bodies, so the addition of aquarium salt can help freshwater fish by minimizing the amount of salt they lose due to stress. The aquarium salt replaces electrolytes and can help with gill functions as well. It is a useful stress remover but too long of an exposure can be even more harmful to fish than the stress itself so it should only be used to help with extreme situations.

Aquarium salt can also be used to help fish diseases, especially those with parasites and infections. It can be useful when used either through a low-dose and long-use routine or a high-dose and short-use salt bath. Not all fish should have salt baths, however, as an already weakened fish can suffer greatly from this method. Before administering a salt bath of any sort, be sure to diagnose the problems with your fish as accurately as possible. There are many online forums and resources where you can ask more experiences fish keepers for advice and second opinions but always take advice with a grain of salt—pardon the pun—because there is a lot of misinformation out there circulating even amongst the aquarium community. Always fact check through reliable resources when treating your fish for any disease.

Gill parasites, specifically Dactylogyrus as seen in this magnification, are one type of parasite that can be effectively fought using aquarium salt. Photo by


Generally speaking, aquarium salt is added as treatment at 1 US teaspoon per 5 US gallons of water. It is important to know the salt tolerance level of the species you are trying to cure, especially if you are adding salt directly to a community tank. This amount if safe for otherwise healthy Betta splendens that have not shown concerning salt sensitivities prior to treatment, though such a thing is rare if at all documented. Too much salt for prolonged periods of time is clearly bad for your fish’s health so it is not advisable to use more than this amount unless you have very specific reasons and the knowledge to do so. A popular idea among betta enthusiasts is that too long an exposure to salt can ultimately damage Betta fish kidneys, though I have yet to find proof to this claim or a scientific study that directly links prolonged aquarium salt use at specific amounts per gallon to kidney failure or damage. While I’m sure that the rumor has links to some study or another, it is not a claim I can directly substantiate nor is it one I will advertise as a definite negative impact for steering away from this salt ratio. Regardless, know how and why to deter from this amount.

Epsom Salt (magnesium sulfate)

Like aquarium salt, Epsom salt is used to treat a wide variety common Betta fish problems. Like with aquarium salt, this salt can be used to treat bacterial and fungal properties in illnesses. Because of this, if a fish has a problem that needs Epsom salt but also appears to be treatable using aquarium salt then it is preferable to use Epsom salt. You should never use both aquarium salt and Epsom salt as this will only harm your fish rather than help him or her.

Unscented Epsom salt is a great non-antibiotic medication to have on hand for fish care. Photo by Morton

This type of salt, however, differs in that it is used to more specifically target internal problems such as swim bladder disorder, constipation, and dropsy. For constipation, Epsom salt should be considered after a controlled fast has been attempted with no result. Epsom salt is a natural laxative, relaxing digestive muscles and making it easier for your fish to pass waste. It is also a different compound, made from magnesium and sulfate rather than sodium and chloride. This is a significant difference. While similar, both salts act differently. Aquarium salt, for example, should not be used for more than one to two weeks but Epsom salt can be safely used long term to fight internal problems.

And unlike aquarium salt, Epsom salt is not necessarily detrimental to live plants and is a good source of magnesium, acting as a plant food supplement. This is important for those who have naturally planted tanks or community species that are salt-sensitive, though it may just be worth separating and isolating sick fish into their own easily-monitored hospital tank in order to risk contamination from illness or treatment regardless of what can and cannot be tolerated. Should you choose to treat in-tank, and have live plants, then Epsom salt is at least one less worry you will have affecting your livestock.

Just remember, like with aquarium salt, Epsom salt should only ever be used as a treatment and never as a preventative.





Burgess, Peter, Dr. “Frequently Asked Questions on Using Salt.” Interview by Matt Clarke. Web log post. Practical Fish Keeping Magazine. Practical Fish Keeping Magazine, 25 May 2010. Web. 28 Mar. 2015. <;

Foster, Dr., and Smith, Dr. “Aquarium Salt Benefits Freshwater Fish.” Doctors Foster and Smith. Doctors Foster and Smith: Veternarian Operated Since 1983, n.d. Web. 03 Apr. 2015. <;

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