Epsom Salt Aquarium Dosage – Differences Between Epsom, Sea and Table Salt

Last Updated on October 21, 2022 by admins

Your fishes are sick and you want to prepare the Epson salt bath? Click to learn all about the proper Epsom salt aquarium dosage.

Epsom salt is the common name for the compound magnesium sulfate, which contains magnesium, sulfate, and oxygen. Did you know that despite its name, Epsom salt does not contain sodium? This means that it is not salt in itself.

Want to know how it works in the treatment of fish and what is the proper Epsom salt aquarium dosage? Keep reading!

What is Epsom Salt?

Epsom salt (also known as magnesium sulfate) is a chemical compound consisting of magnesium, sulfur, and oxygen. It owes its name to the city of Epsom in Surrey, England, where it was originally discovered.

This type of salt has been used for hundreds of years to treat ailments, such as constipation, insomnia, and fibromyalgia.

Differences Between Aquarium, Epsom, Sea, and Table Salt

Table salt

Table salt should not be used in an aquarium. It has iodine and anti-caking agents mixed in to prevent it from clumping in the shaker. Such substances are very harmful to your aquarium pets.

Sea salt

Sea salt is essential for saltwater tanks but is deadly for freshwater fish. Therefore, be careful. It will help you create the levels of pH, hardness, and salinity needed for marine animals.

Aquarium salt

Aquarium salt was created to help you remove many harmful buffers that are deadly to freshwater fish. It also improves the function of gills, promotes slime coat, and reduces nitrate uptake.

Epsom salt

Epsom salt doesn’t contain elements found in sea salt, and therefore it isn’t dangerous for freshwater aquarium pets. In addition, it is not as processed as table or aquarium salt, which makes it less harsh in the water column. Epsom salt in the fish tank helps treat constipation, swim bladder disease, and dropsy.

how does epsom salt cure fish

How Does Epsom Salt Cure Fish?

Epsom salt can be used to treat the following three conditions.


If you over-feed your fish or their diet is low in fiber, it can lead to constipation. Constipation is most easily recognized by the loss of appetite and bloating in the belly area. You can first stop feeding your fish for 24 to 48 hours to see if it will improve the condition. If not, then you can add Epsom salt to a fish tank.

Quarantine the fish and dose one tablespoon of salt per gallon of water in the tank for around 15 minutes. This will allow your sick fish to get rid of the waste.

Swim Bladder Disease

Constipation, intestinal parasites, and high nitrate levels in the water column are the most common causes of swim bladder disease. If you notice your fish struggling to stay upright or swimming on its side or even upside down, consider a salt treatment.

The ideal Epsom salt aquarium dosage for treating swim bladder disease is one teaspoon of salt for every one gallon of water in your quarantine tank.


Dropsy is no joke. It leads to kidney failure and can be fatal. You will easily recognize this, as the abdominal region will most often be bloated, and the scales will be raised. Epsom salt for fish will relieve swelling in the abdominal area and allow the shell to return to its normal position.

Use 1/8 teaspoon for every five gallons of water. This will be the bath that treats the whole tank. It is important to combine this type of treatment with other recovery treatments. In combination with antibiotics, Epsom salt can relieve swelling.

Remember, never use aquarium salt or any other type of sodium to treat a fish with dropsy as this can make the condition worse.

Altering Water Conditions

Did you know that you can use Epsom salt to change the current state of your water? For example, it helps increase the hardness of the water in freshwater fish tanks. This is primarily because hard water contains more dissolved calcium and magnesium than soft water. Keep in mind that it is not always necessary to change the hardness of the water as some fish prefer soft over hard water and vice versa.

If you want to change the chemistry of your aquarium water, feel free to add 1 milliliter of Epsom salt per 10 liters of water. This will result in an increase in permanent hardness by approximately 70 mg / L CaCO3.

In addition, water hardness can affect pH levels because hard water is alkaline, while soft water is more acidic. Try to avoid any pH changes greater than 0.3 in any 24 hours. Finally, monitor the changes carefully to preserve the health of your aquatic world.

How To Make an Epsom Salt Bath?

First, prepare the quarantine tank. Choose the one that is at least one gallon in size. The ideal Epsom salt aquarium dosage can range from one teaspoon to one tablespoon for each gallon of water, depending on needs. Allow it to dissolve completely in the water.

Then, prepare a revival tank. Then, prepare a revival tank. Try to make it contain 1/4 treated salt bath and 3/4 aquarium water. Take the fish out of the aquarium and put it in a treatment tank. During the Epsom salt bath, make sure that your fish don’t faint or jump out of the tank.

At the end of the treatment, transfer your pet to the revival tank. This step is crucial because it will allow your fish to get used to the less salty conditions before returning to the usual water column in your home aquarium.

After a few minutes spent in the revival tank, it is time to head home. Carefully transfer your pet from the revival container to the aquarium. Remember to observe it for a few minutes to make sure it acclimatizes properly again.

Learn more about Your Number One Guide On Saltwater Aquarium Salinity Level


Epsom salt is a chemical compound that contains magnesium, oxygen, and sulfur. It is used to treat human ailments, such as constipation, fibromyalgia, and insomnia. It can also be used for treating fish suffering from dropsy, swim bladder disease, and constipation. So, we have to admit that it has a fairly wide use.

However, before purchasing and using Epsom salt, try to contact your veterinarian or the local pet store where you bought your fish to make sure that you are getting the right product.

We hope you found this article on Epsom salt aquarium dosage useful. Do you have additional questions or comments? Write to us in the comments below!

Read more about The Best Freshwater Aquarium Test Kit