Salt in freshwater aquarium yes or noAdding salt in freshwater aquariums is a question that fish enthusiasts hotly debate. An online search will turn up countless articles explaining the myriad benefits of adding salt to your tank.

However, you will find just as many articles advising you not to add salt.

While adding salt to a freshwater fish tank may seem contradictory, some aquarists believe adding salt will benefit the fish. Although not all experts believe salt in a freshwater tank is good, everyone agrees that using the right salt is essential.

In this article, we will consider the reasons to add salt to your freshwater aquarium. It will also explain the correct type of salt to use that will benefit your fish in your aquarium. It also tells you why salt is not always beneficial.

Why Add Salt to a Freshwater Aquarium?

Hobbyists have been adding salt to their freshwater aquariums for quite some time. Some fishkeepers regularly add salt to a tank to reduce stress, as medication or create a suitable environment for fish species from brackish water.

Aquarists who add salt to the tank assert that keeping your freshwater tank lightly salted can improve the health of your fish. They believe salt helps to protect fish from parasitic infections and cure some diseases.

Different Types of Salt

1. Freshwater Aquarium Salt

Freshwater aquarium salt is also called “tonic salt” or “livebearer salt.” Some brands are just plain sodium chloride, while others contain small amounts of other mineral salts that help buffer against pH changes.

Freshwater aquarium salt is made from evaporated seawater. Since it’s made specifically for use in freshwater aquariums, it doesn’t have additives like iodine or anti-caking agents such as calcium silicate.

Freshwater aquarium salt is very different from the table salt you have in the kitchen.

Table salt used for cooking has additives, so it is best not to add it to an aquarium.

Freshwater aquarium salt comes in small boxes and is readily available online and from your local fish or pet shop.

2. Marine aquarium salt

Marine aquarium salt is designed to replicate seawater, so it has a similar mineral composition to natural seawater. However, it has a higher buffering capability, allowing it to resist pH fluctuations between water changes.

Marine aquarium salt is more expensive than freshwater salt. It is typically sold in large boxes, bags, or buckets.

3. Non-iodized rock salt and kosher salt

These two salts are pure sodium chloride. They don’t have any extra ingredients added to them. As a result, they are favorites for fish keepers who like to add salt to freshwater tanks.

How does Aquarium Salt Help?

Many hobbyists say that keeping your freshwater tank salted lightly with aquarium salt is good for your fish. It is a handy remedy for the treatment of several common fish diseases and injuries. Aquarium salt also acts as a preventative measure against some parasitic infections and diseases.

Some other good reasons to use aquarium salt are that it boosts the gills’ functions and provides essential electrolytes. Salt also serves to minimize stress and supports the general wellbeing of your pets as it assists with maintaining water parameters.

– Osmoregulation

Osmotic regulation is one reason that comes most often for adding aquarium salt to your freshwater aquarium.

By nature, freshwater fish are saltier than the water they live in. Their skin is semi-permeable, so they take tank water into their bodies. In simple words, this is the process of osmoregulation.

Your fish releases vast amounts of salts and electrolytes through urination, and some freshwater fish can lose their body weight in urine in three or four days. They need to reabsorb salt from the tank to balance the concentration of salts and electrolytes in their bodies.

Your aquarium water tries to even out the salinity of your fish with the saltiness of your aquarium. However, if your fish cannot absorb sufficient electrolytes from the water if they are sick or under stress, they suffer from osmotic shock.

When you gently boost the salt level in your tank, it makes it easier for your fish as their cells have to make less effort.

– Balancing Water Chemistry

Another use of aquarium salt is to bring down nitrate levels and prevent nitrate poisoning from harming the fish in your tank.

Nitrates are a natural by-product of your fishes’ excretions. If your tank is new, or your filter suddenly stops working, the nitrate levels in your tank can become toxic if there aren’t sufficient beneficial bacteria to absorb the nitrate.

Suppose you take steps quickly to remedy this and add aquarium salt at a proportion of 30 times the amount of nitrate in the water. In that case, the chloride ions will form a natural barrier that will prevent your fish from absorbing the nitrates.

You could even add less salt. Maybe 0.004 ounces (100 mg) salt per liter would be adequate, so all freshwater fish species can comfortably tolerate it. Adding aquarium salt will give you time to install a new filter long-term solution to the problem.

– Removal of Fungal or Parasitic Infections

A salt bath made with aquarium salt is a quick and efficient method of eliminating some types of external parasites from your fish.

Aquarium salt upsets the balance of salt to water in the cells of harmful organisms such as parasites, bacteria, or fungus on the skin, gills, and fins of your fish. It dehydrates these tiny microorganisms and kills them.

The aquarium salt bath can also help stimulate the production of your fish’s protective slime coat, enabling them to fight off disease. If your fish has little white fluffs of fungal growths, you can dip them in a salt bath to get rid of the fungus. Finally, a salt bath can help clean the build-up of excess mucus from the gills of your fish.

Is Aquarium Salt Good For Freshwater Fish?

Not all freshwater fish tolerate salt. Some fish, like goldfish or cichlids, enjoy a little aquarium salt in their freshwater aquarium. For goldfish, in particular, aquarium salt can be a good cure for some of their common ailments.

However, there are some other fish that react poorly to salt.

Some barbs, livebearers, corydoras, tetras, catfish, koi, and South American tetras don’t do well if you add salt to the water. Salt can make them lose their balance, and they will roll over while swimming. If you don’t act fast to remove them from the tank at this point, your fish may die.

Some invertebrates, such as snails, are also very sensitive to salt, so if you use zeolite to bring down the level of ammonia in your freshwater tank, you can reverse during a salt treatment. It would be best to ensure you remove all invertebrates and any zeolite before using salt.

Studies have shown that fry doesn’t tolerate salt, so putting young fish in a tank with salted water is not advisable.

Is Aquarium Salt Good For Plants?

Aponogeton undulatus in aquariumMost freshwater aquarium plants don’t thrive in salted water, and even a small amount is harmful. Plants can dry out and die.

While some plant species are less sensitive to salt than others, it is wiser not to add salt to your aquarium if you have any live plants in it.

However, freshwater aquarium salt helps keep your aquarium free of algae. Since algae don’t tolerate salt, it dies when you add salt to the tank.

As a result, a salt treatment can help you keep your tank clean by banishing all traces of algae from the floor and walls of your tank.

How to Add Aquarium Salt to a Freshwater Tank

When you add aquarium salt to a freshwater tank, you must not add it directly into the tank. It would be best to dissolve the salt separately in a cup before adding it to your tank.

Dissolving the salt in water keeps your fish safe from burns if the salt falls directly on them. You could also face more severe problems if the fish eat the salt.

There are some breeds of fish and plants that are very sensitive to salt. Some of them can tolerate a little salt for short periods, but try to avoid salting your water if you keep species like loaches, catfish, and snails. Some invertebrates and most freshwater plants also do not flourish in salted aquariums.

When you use freshwater aquarium salt to treat an illness, start with the lowest dose possible. However, it might take some time before you see an improvement, so you must be patient.

When you use aquarium salt, you’ll want to consider that a more refined grain salt will dissolve much faster than a coarser rock salt. Furthermore, salt does not evaporate from the tank along with the water, and neither is it removed through filtration.

The only time you will remove salt from the tank is when you do a water change. You must consider this if you want to add more salt.


This guide has shared information about aquarium salt and its benefits and uses. It also tells you the drawbacks and how to add them to your tank. Here is a quick summary to assist you.

Essential Characteristics of Aquarium Salt:

  • It does not contain additives, artificial colors, or anti-caking ingredients, unlike table salt.
  • It does not alter the water pH.
  • Aquarium Salt replenishes the natural electrolytes in the tank.
  • Benefits of Aquarium Salt:
  • It promotes gill function
  • It encourages the production of a healthy slime coating.
  • It assists with water chemistry.
  • It provides electrolytes to fish.
  • It reduces stress.
  • It boosts osmoregulation.
  • It removes the growth of algae in the tank.
  • It helps to heal mild infections.
  • It is used as a bath to prevent and treat diseases.
  • It helps to heal wounds.
  • Drawbacks of aquarium salt:
  • Not all ornamental fish tolerate salt
  • Most freshwater plants do not thrive in salted water and will die.
  • Salt doesn’t evaporate, so your tank can become over-salted

Adding salt in freshwater aquariumAquarists hold varying opinions on keeping the water in the tank salted at all times. However, most agree that aquarium salt has many benefits.

If you decide to use it in your aquarium, please thoroughly research and use it in the proper dosage.

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