Using Salt in Freshwater Aquariums

Updated on November 03, 2021
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Education and Compliance (ACE) Team
freshwater aquarium

Can you use salt in a freshwater aquarium and how much?

Yes, adding 1 tablespoon of freshwater aquarium salt per 5 gallons of water can provide a number of benefits to your aquatic ecosystem. Be sure to only use  freshwater aquarium salt (NOT marine salt) that has been made from evaporated seawater, as other types can harm your fish.

If you are unsure of how much salt is in your aquarium, especially after a water change, the use of a refractometer is the most precise way to measure the specific gravity in your aquarium. 

Remember, for the health of your aquatic life, changing water parameters should be done gradually so be careful not to change your specific gravity more than 0.001 in a 24-hour period.

Even though this product is natural, caution should be taken as certain species of fish, especially scaleless fish, and plants are very sensitive to the effects of increased salinity in their habitat. It is best to follow the directions on the product, confer with your local aquatic specialist or reach out to the manufacturer’s customer service line if you have any questions.

The benefits of using salt in a freshwater aquarium

There are many benefits to using freshwater aquarium salt in your freshwater aquarium! Although it is made from evaporated sea salt, it is not the same as the salt used in marine aquariums. Don’t be salty though, let’s dive into the benefits and uses of this natural supplement to gain a better understanding of how it could help improve the overall health of your aquatic life!

This all-natural salt is made from evaporated sea water and promotes healthy gill function while reducing stress and the loss of electrolytes. Additionally, it promotes your fish’s slime coat and can even help heal wounds. 

Freshwater aquarium salt can assist with some parasitic infections and will help improve the efficiency of medications. In addition to the medication, salt can be utilized for baths or dips to combat external parasitic infections. Baths and dips are a little different than the salt levels maintained everyday within the aquarium.

Marine salt and freshwater plants

Marine salt is more than just a type of salt found in the ocean; it contains additional elements like magnesium, calcium and others that recreate water found in your pet’s natural habitat. The salt and these extra elements can be vital to the health of saltwater fish, but shouldn’t be used with freshwater plants. 

The extra additives and salt levels in marine salt are designed to support the growth of coral; freshwater plants have very different needs when it comes to nutrients. That’s why you should only use freshwater aquarium salt in planted tanks that feature freshwater flora.

Ways to Use Salt in a Freshwater Aquarium

Salt Bath

For a bath, you need to utilize one teaspoon of freshwater salt per gallon of aquarium water. This is dissolved in a separate container, then slowly poured into the aquarium. This treatment is typically maintained for three to four weeks. If utilizing the bath treatment, you will need to complete weekly water changes of at least 25% to slowly reduce the salt content, preventing shock to the fish.

Dip

With a severe parasite infection, a dip may be needed. A dip is a little different than a bath and as the name implies will be performed outside the aquarium in a separate container. For this, you will completely dissolve 5 tablespoons of freshwater salt in a container containing a gallon of aquarium water prior to introducing a fish. The fish should be placed in this salt-heavy water for minimum of 5 minutes however, it can be extended to thirty minutes if the fish is not showing signs of stress. If the fish is showing any signs of stress, like laying on its side, immediately return it back to the aquarium.  Be sure to dispose of the dip solution- do not pour it into your aquarium.

Reducing Nitrite, osmotic stress and maintaining effectiveness

Nitrite becomes toxic to fish at a concentration of 0.1 ppm (part per million). The chloride in the salt can help to reduce the toxic effects of nitrite on aquatic life. Due to the concern of nitrite poisoning, salt can be extremely beneficial during the cycling period in a new aquarium setup, inhibiting nitrite intake.

A fish’s body is continuously busy with osmoregulation. This is the process of maintaining the internal balance of salt and water, therefore aquarium salt may also assist with reducing some osmotic stress. 

For aquarium salt to be most effective, its generally recommended to dose after starting up a new aquarium and every time you complete a water change. Remember, salt does not evaporate, so it is imperative to conduct regular water changes and monitor specific gravity levels to ensure you do not accidentally accumulate higher salt concentrations within your tank.

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