Is Aquarium Salt Necessary in Freshwater Tanks?

The fishkeeping community has a few controversial issues that aquarists can’t seem to agree upon, and the necessity of aquarium salt in freshwater tanks is one of them. A quick search will reveal fervent advocates on both sides. And the truth is it’s quite challenging to decide which side is right, as they both make some solid points. We’ll go through all these aspects one by one to see which argument is valid and which are the instances when adding salt to freshwater tanks is necessary.  We’ll also see what kind of salt to use, as that’s a separate controversy altogether.

Should We Use Aquarium Salt in Freshwater Tanks?

When it comes to aquarium salt being used in freshwater tanks, the balance between benefits and dangers doesn’t clearly weigh on one side. Even turning to the expertise of seasoned aquarists doesn’t help that much, since they disagree. There are two extreme positions. Some say you should under no circumstance add salt to your freshwater tank. Others claim a small quantity of aquarium salt should be added regularly to help osmoregulation and prevent parasites and illnesses.

It’s hard to decide exactly what salt does to your freshwater fish and at what point the risks start to outweigh the positive outcomes. But all aquarists agree that many health issues your freshwater fish may have can be solved with a temporary treatment involving aquarium salt. The fact that algae and parasites don’t survive the saltwater treatment is also well known. So, if used wisely and correctly, aquarium salt has its undeniable benefits to the freshwater environment you have created in your home.

What Is Aquarium Salt?

Aquarium salt, generally speaking, is salt you add to your fish tank to help your fish heal or prevent an outburst of algae or parasites. However, there are quite a few options, each with its own pros and cons. Before adding salt to freshwater aquarium, you need to decide if it’s indispensable and what type of salt better suits your needs. And if you’re wondering what is aquarium salt made of, let’s take a closer look at our options.

Is table salt ok?

The first question probably anyone thinks of is, ‘can we use table salt in freshwater fishtanks?’. It’s a reasonable question and, at the same time, another controversy. Some people will tell you it’s ok to use table salt in an aquarium, as long as it’s non-iodized and has no additives. Most aquarists will tell you the aquarium salt vs. table salt debate shouldn’t even exist, and that you should under no circumstance add table salt to your fish tank.

But what is the difference between aquarium salt and table salt? Table salt or sodium chloride contains the following elements: iodine, potassium, and a caking agent that protects salt against humidity. That’s not a good combination to add to your fish tank. Even if you get non-iodized table salt, you still have to worry about the caking agent and other additives it may contain, and that can be harmful to your fish.

Aquarium salt is created precisely for this usage, and you can be sure it won’t hurt your fish, at least not if you use it for short periods, as treatment. We’ll discuss long-term usage and whether it’s a good idea a bit later. For now, let’s take a closer look at our options.

Types of aquarium salt

Freshwater aquarium salt, or tonic salt, is, in fact, evaporated seawater. It’s nature’s recipe, free of any additives or harmful elements. Also known as livebearer salt, it can be used as a mild antiseptic and can contain small quantities of minerals that help you keep the PH-level in the aquarium under balance.

Non-iodized rock salt and Kosher salt are actually pure sodium chloride, so they are a great option not only for temporary usage in freshwater tanks but also on your table since it has absolutely no additives.

Marine salt is a unique mix created with your fish’s health in mind. It has added minerals like magnesium or calcium that can actually help the inhabitants of your tank.

How Does Salt Work?

Even if there are many voices who reject it, salt can sometimes be very beneficial to your aquarium. Your first thought could be that it makes no sense to add salt in a freshwater tank, but the truth is it has its uses. The reason is your freshwater fish have quite a salty interior, which needs to remain at the same level through the exchanges between their bodies and the water inside the tank. That’s a demanding process for their organism, and when they are ill, they need a little extra help to keep the process going.

If you’re wondering what does aquarium salt do for fish, here is the answer. Aquarium salt works as a treatment for many problems your fish may have, from parasites and illnesses to algae infestation and nitrite poisoning. It sounds like an excellent solution for many issues your aquarium may have, so why the controversy? To make things more clear, let’s look at the pros and cons of adding aquarium salt to freshwater tanks.

Also read – The Best Algae Eaters for Any Freshwater Aquarium

Aquarium salt benefits

  • It helps fish maintain a high level of salt in their bodies. They particularly need that help when they are injured, as they will actually leak salt through the wound, and without any salt added to the tank, it will be harder for them to regain balance and heal.
  • It seems to prevent the appearance of parasites or fungi: roundworm, tapeworm, thorny-headed worms, or flukes
  • It reduces the level of nitrates in the aquarium water when the beneficial bacteria in your tank cannot keep it under control
  • It helps fish grow the protective slime coating on their bodies more easily
  • Some fishkeepers claim using salt on a regular basis reduces the stress level of their tank inhabitants
  • It clears the mucus off the gills

Detriments of using aquarium salt in a freshwater tank

  • You must keep in mind that the salt you add won’t evaporate, so if you plan to add some more, don’t do it before a water change. It’s crucial to learn how to use aquarium salt before trying it
  • Most freshwater plants won’t like the salt, and some of them will actually dehydrate and die
  • Some fish won’t tolerate the added salt, so you need to observe them closely if you decide to add aquarium salt; you may actually notice they are rolling over
  • If you mess up the dosage and add too much, aquarium salt can kill your fish because it will affect their kidneys
  • If your aquarium is well-maintained and clean, and you are testing and changing the water on a regular basis, there is no need to use salt as a prevention method
  • Snails and other invertebrates are very sensitive to salt
  • If the dose is too high, it can irritate the gills and increase the production of mucus

Osmoregulation and Aquarium Salt

Osmoregulation is the process that regulates the salt level in your fish’s body. More specifically, its organism is continually struggling to keep its internal salinity at a constant level, while the freshwater it lives in always tries to dilute it. Fish have fragile skin, even more so around the gills, and that’s where the freshwater gets inside by diffusion or osmosis.

Fish use osmoregulation to fight these changes in salinity and maintain the level their bodies need. They do that with a lot of help from their kidneys, which help them eliminate the water quickly. But before releasing urine, they absorb salt from it, to cut their losses. Apart from that, their gills are equipped with special cells that help them absorb salt from the water.

It’s a process that works pretty well, so why would we mess with it by adding aquarium salt? We usually don’t need to, but when the fish is ill, or the balance in the aquarium is affected by algae or unwanted bacteria and parasites, some help is necessary. Other than that, if your aquarium is clean and your fish are healthy and seem happy, there is no real reason to add salt as a prevention method.

How to Add Aquarium Salt?

Veterinarians do not recommend salt as a permanent addition to a freshwater aquarium. But if you need to use it as a temporary treatment, the first step is to find out how much aquarium salt per gallon you should add. The standard dose is 1-5 ppt if your fish have wounds or parasites. A persistent question, especially among beginners, is, ‘Can I add aquarium salt directly to the tank?’ The answer is no; the best way of adding salt to aquarium is to mix it in a bucket to make sure it’s completely dissolved before you place it inside the tank.

If the health issue your fish have is more serious, you can try a dip or medicinal salt bath for fish. In that case, the maximum dose is 30-35 ppt, but the exposure should be under 4 or 5 minutes. You also must observe your fish closely, and if you see any sign of distress, remove them from the saltwater. Knowing how much salt to add is essential, and so is deciding whether it’s absolutely necessary.

Also read – How to Use RODI Water to Create the Best Water for Your Aquarium

Aquarium Salt for Parasites

Aquarium salt can be a lifesaver in many situations, and parasite infections are the best example. At some point during your fishkeeping experience, you can face the unpleasant problem of internal or external parasites. Fish are fragile creatures, so treatments must be suitable and applied correctly, to make sure you aren’t making the matter worse. When it comes to parasites, salt has been known as an excellent treatment for a long time.

Parasites and fungi don’t survive an aquarium salt attack. External parasites that attach themselves to your fish( like Chilodonella, Trichodina, and Costia) will dehydrate from the salt and eventually let go and die. Once released, the fish will be able to heal their skin by producing extra slime coating. The white and fluffy fungi you may notice on your fish can also be destroyed by adding aquarium salt for a short period.

How to Perform a Medicinal Salt Dip

The medicinal salt dip for fish is a pretty extreme measure. So not only do you need to know precisely how much aquarium salt you should use, but you also have to be absolutely sure it’s necessary. From using Epsom salt bath for bladder infection to healing wounds or fight specific disease, a saltwater dip for freshwater fish can be extremely useful if done correctly. If you are interested in how to set up a salt dip with aquarium salt for betas or other fish, this is how to perform a salt dip correctly:

  • First of all, the salt dip, sometimes called a medicinal salt bath, should never be done inside the tank; you will need a separate container
  • Add four teaspoons of salt per gallon in the bucket or container you have chosen
  • Start adding water slowly so that it can dissolve easily
  • You need to add water from the tank, to have the same temperature and PH-level and not cause unnecessary stress to your already diseased fish
  • To be on the safe side, don’t keep the fish there for more than 30 minutes, and take it out at the first sign it’s starting to feel stressed
  • Once the treatment is over, move the fish in an isolation tank, until you clean and treat the rest of the tank as well; immediately placing the fish back in the tank would erase any effect of the treatment
  • Make sure the water in the isolation tank has the same temperature and PH level to avoid further stress for the fish

What Are the Best Aquarium Salts for Freshwater Tanks?

Once you know what your aquarium salt should contain, or more specifically, what you need to make sure it doesn’t contain, you will have no problem finding the right product. If you don’t want to use Kosher salt and prefer to buy a package specially created for fish, there are quite a few good options on Amazon. Here is our selection:

#1 – API Aquarium Salt Freshwater Aquarium Salt

API is one of the top brands when it comes to fish treatments, so if you’re wondering what is in API aquarium salt, the answer is salt and electrolytes; it’s a product you can use without any restraint. In some cases, if necessary, you can pair it with some of the other treatments from API, and you will quickly get rid of whatever problem your fish are facing.


  • Clear instructions, if you aren’t sure how to use API aquarium salt
  • Great if you want to reset your nitrates media bag
  • The box has good size, and it comes at a reasonable price
  • Excellent for a betta salt bath, if they have an infection
  • Great for quarantine tanks


  • Some boxes contain larger particles; you can still use them, but they will take longer to dissolve
  • Not suitable for plecos

#2 – Imagitarium Aquarium Salt

This is an aquarium salt made in the USA, and an excellent choice if you need to improve the gill function of your fish, or simply reduce their stress and balance their electrolytes. This product is created particularly for freshwater tanks, so if you use the right dosage, you will have no issues with it. If you use it with Seachem Prime Freshwater Conditioner, you will have no problem keeping your aquarium clean and healthy.


  • This aquarium salt enhances the efficiency of the medication you give your fish and helps them heal faster
  • It removes the unwanted and dangerous effects of nitrites
  • It’s a natural salt made from evaporated seawater, so it has no dangerous additives


  • For this price or one close to it, you can get aquarium salt from a well-known brand (not that this one isn’t ok)

#3 – Jungle NJ007 Aquarium Salt, 1-Pound

If you need aquarium salt for tropical fish, this product from Jungle may be what you are looking for. It brings beneficial electrolytes and helps keep the aquarium clean and the fish healthy and happy. However, before you start using it, make sure you know what tropical freshwater fish can tolerate aquarium salt, to prevent unpleasant surprises.


  • Useful against goldfish bacterial infections
  • You can use it to hatch Brine Shrimp eggs
  • It can help reduce the stress of your fish


  • The zip closure doesn’t always work well

#4 – SunGrow Aquarium Salt for Betta Fish

This product is for betta lovers. If you plan on treating betta with aquarium salt, try this one from SunGrow. It will provide the level of electrolytes you little betas need; it will improve their coloration and vitality. Salt in the betta tank will improve their kidney function, increase the production of that protective slime coating, and it’s an excellent betta parasite treatment.


  • Great for removing betta external parasites
  • Helps reduce the level of stress
  • Useful when you set up a new freshwater tank; just find out how much aquarium salt per gallon for betta you should use, and you are good to go
  • Great for a betta salt bath


  • You may want to move the salt from the zip bag to a closed jar

Aquarium Salt vs. Epsom

If you prefer to buy a type of salt both you and your fish can benefit from, Epsom salt may be what you need. You have occasionally enjoyed a relaxing Epsom salt bath, but did you know your fish will like it as well? We use Epsom salt because it has laxative and anti-inflammatory effects, and that’s exactly why fish can benefit from it.

You can use Epsom salt for fish if they are bloated or constipated and need help. As for the anti-inflammatory effects, those are definitely good for fish too. You can use it to reduce swelling, or turn to Epsom salt treatment for fish popeye, or to reduce pressure from dropsy. People also frequently use Epsom salt for swim bladder disease; it helps them swim easier and even sink.

As for how much Epsom salt for freshwater aquarium, the right dosage is one tablespoon per gallon of water, so measure carefully to avoid an unwanted Epsom salt overdose, and allow your fish to relax exactly the way you do.

What’s the difference? While Epsom salt is magnesium sulfate, aquarium salt is sodium chloride. And, as we mentioned above, its beneficial effects are a bit more impressive than the one of Epsom salt. However, depending on the situation, both can have their uses.

What Are the Aquarium Salt Overdose Symptoms?

Can you overdose on salt? You probably won’t, but when it comes to aquarium salt, your fish can be in danger if you add too much. It’s not really clear what the salt overdose amount is, but just to be safe, stick to the instructions on the package and on the information we provided above.

The symptoms of salt overdose in fish aren’t very well documented, but there are a few things you can keep an eye on. First of all, if the water in the tank is too salty, it will affect osmoregulation; the fish will lose salt through osmosis, and the organism will have to make efforts to compensate. An overdose of salt can dehydrate the fish, or it can cause excessive growth of the slime coat.

If you notice that your fish is moving slower than usual, hangs out at the bottom of the tank, and has difficulty breathing, you need to take measures, meaning a partial water change. As for the long-term effects of a salt overdose, they are also unclear. But it is possible that it can affect the gills and add stress to internal organs; their bodies will definitely be unbalanced for a while.

Also read – How to Choose the Best Aquarium Driftwood

What Aquarium Fish Don’t Like Salt in the Water?

It’s mainly the scaleless fish species that have an extremely low tolerance to salt. Scales would have provided a protective layer, and they don’t have it. Corydoras, for example, don’t accept salt at all. Tetras will also be very unhappy if you add aquarium salt. The best thing to do when you want to buy fish for your aquarium is to ask for information on their tolerance to salt. Another aspect to keep in mind is that fry and young fish don’t tolerate aquarium salt the same way as adults. So, if you need to treat them, you will have to use a hospital tank and adjust the level of salt.

FAQs on Aquarium Salt

Will aquarium salt raise ph? It depends on what type of salt you use. Regular aquarium salt, or tonic salt, won’t make much of a difference. But if you use marine salt, you will have to test the PH level of the water, because changes will occur.

Do I have to remove decor when putting aquarium salt? No, it’s not necessary to remove the decor when adding aquarium salt. Since salt fights off algae, it will also help clean the pieces of scenery as well. You can, however, take the decor out once in a while when you do a water change to clean it thoroughly.

How do you know if salt is properly dissolved in an aquarium? Adding aquarium salt straight to the tank is a bad idea, as it’s hard to make sure it dissolves and to check if there are any granules left. That’s why you need to use a separate container, with water from the tank, to watch the salt dissolve carefully. It’s also a good idea to buy fine salt, not large granules.

How to use aquarium salt for Ich? Ich, or white spot disease, is a widespread disease among freshwater fish. To get rid of it, use one tablespoon of salt per three gallons of water. This is a low dose, but it will do the trick.

How often can you use aquarium salt? As seen above, not all aquarists agree on this aspect. Some use a small dose with every water change to prevent problems and lower the stress level of their fish. Others consider such intervention unnecessary if the fish don’t show any sign of distress. The safest way is only to use aquarium salt when you need to treat a disease or remove parasites and algae. The frequency is something you will establish by keeping a close eye on your aquarium.

What aquarium plants will tolerate salt? Freshwater plants don’t usually appreciate it when you add aquarium salt in the tank. It has a similar effect as on algae, dehydrating them. So, if you plan on using salt, you may want to go for the types of plants people usually place in brackish aquariums. Here are a few examples: Anubias, Java Moss, or Java Fern.

Read here about how to care for aquarium plants.

Does Epsom salt expire? You would expect salt, in general, to be forever valid, and yet many times, you find an expiration date on your package. However, Epsom salt doesn’t expire. But in time, it can get hard and challenging to use.

What are the most common diseases you can treat with aquarium salt? Aquarium salt is a very versatile treatment and has many benefits for your aquarium if used correctly. It’s especially beneficial in these cases: using aquarium salt to treat popeye, mild cases of fin rot, dropsy, Ich; you can also use aquarium salt to treat columnaris.

So Is Aquarium Salt Necessary in Freshwater Tanks?

This is one of the cases when your intuition may be wrong. Adding salt to a freshwater tank doesn’t sound like a good idea at first. But the truth is it can be highly beneficial in certain situations. After going through all the aspects we have presented, it’s up to you to decide on which part of the ‘barricade’ you stand. Do you think aquarium salt should be on the daily menu or something to be avoided altogether?

The medium path is probably the best. Aquarium salt has proven its efficiency in treating numerous illnesses and solving essential problems in your aquarium, so completely ignoring it is not a good idea. As with many other things, it’s all about moderation and knowledge to recognize the instances when it’s actually necessary. A firm opinion on this matter is something you will probably develop in time, after having enough fishkeeping experiences to reach a relevant conclusion.

Also check out – Everything You Need to Know About Fish Food

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