Table Salt Vs Aquarium Salt

Table Salt Vs Aquarium Salt: Which One Is Safe for Fish?

Salt aka Sodium Chloride is very important for the human body. This is because the body uses it to maintain blood pressure, to maintain fluid balance, and to absorb and transport nutrients. Salt made for adding to food is commonly referred to as table salt.

Salt is also very important for fish. It is important for saltwater fish because, without adequate amounts of it in water, the fish will absorb too much water and die. Many experienced aquarium hobbyists also occasionally add salt to their freshwater aquariums for one reason or the other. Salt specifically made for adding to aquariums is referred to as aquarium salt.

In this post, you will learn everything important you need to know about table salt, aquarium salt, and fish.

Is Table Salt Safe for Fish?

The short answer is no. Table salt is good for us human beings because it has several benefits as stated in the intro above. However, it is not safe for fish. This is because it usually contains additives such as iodine and calcium silicate that are harmful to fish. 

Iodine is added to table salt to prevent iodine deficiency, which often leads to developmental and intellectual disabilities in humans. While iodine is beneficial to humans, it can cause iodine toxicity in both saltwater and freshwater fish especially when added to aquariums in large quantities. 

Calcium silicate is normally added to table salt to prevent it from caking/ forming lumps. However, it is harmful to fish. When added to aquariums in large quantities or frequently, it can kill both saltwater and freshwater fish. 

Therefore, because of the harmful additives in it (iodine and calcium silicate), table salt is not safe for fish and should not be added to aquariums. 

Is Aquarium Salt Safe for Fish?

Aquarium salt is the best and safest salt to add to saltwater and freshwater fish tanks. This is because it is specifically made to benefit and not to harm aquarium fish. 

The number one reason why experienced aquarists add aquarium salt to their tanks is to inhibit the growth of algae. Occasionally adding a bit of salt to a freshwater tank will prevent the growth of algae as it will make the aquarium water unsuitable for them to thrive. So if you don’t want to see white moldy stuff or green slimy stuff on your fish tank glass, you should consider periodically adding some aquarium salt to your freshwater tank.

Another reason why experienced aquarists occasionally add salt to their fish tanks is to kill fungi and pathogens. Therefore, if you want to reduce the likelihood of your fish suffering from common fish diseases, you should consider periodically adding aquarium salt to your freshwater fish tank.

Experienced aquarists also add aquarium salt to their fish tanks to boost the immunity of their fish. This is because salt enables freshwater fish to produce a thicker protective slime covering to shield them from pathogens and diseases.

As you can see from the information above, adding aquarium salt to fish tanks has many benefits. However, adding too much aquarium salt is not recommended. This is because too much salt in a freshwater tank can kill fish. 

What to Consider Before Adding Salt to a Freshwater Tank

Since freshwater fish can be killed by too much salt, you should never add aquarium salt regularly to your freshwater tank. You should only add aquarium salt occasionally and for specific reasons. And before you add salt, you should consider the following things. 

  1. Type of Salt to Use

As mentioned above, the safest and best type of salt to add to a fish tank is aquarium salt. If you are tempted to use the table salt in your kitchen, you should resist the temptation. This is because table salt has additives that are dangerous to fish. 

  1. Type of Fish in Your Aquarium 

Some fish species can die even when exposed to somewhat tiny amounts of aquarium salt. Therefore, before adding salt to your freshwater aquarium, you should research their salt tolerance and you should only add small amounts of salt that will not negatively affect your fish.

  1. Quantity of Salt to Add

It is very important to know your fish’s tolerance to salt before adding salt to your aquarium. And when you do, you should never give them more than they need. In case you are not sure of how much salt to add to your freshwater tank and you want to use salt as medicine, use a 1 tablespoon for every 3 gallons of water. This amount of salt is usually effective and is extremely safe for virtually all fish species.

  1. The situation 

Salt is medicine. Experienced aquarium hobbyists only use it as medicine to cure or prevent common fish diseases. As stated earlier, it has other benefits. It can prevent fungi and it can stop algae infestation. However, since freshwater fish are not used to increased concentrations of salt, you should only use salt as medicine and find other means to get its other benefits. For instance, instead of using salt to stop an algae infestation, you can use a harmless UV sterilizing aquarium light.

As you can see above, there are many things to consider before adding salt to a freshwater tank. You should take them into account if you want your fish to thrive and have a long lifespan. 

The Best Aquarium Salts for Freshwater Fish on the Market

Here are some of the best aquarium salts for freshwater tanks and their pros and cons. Most of the aquarium salts below are normally added by experienced aquarium hobbyists to cure common fish fungal diseases such as gill rot, tail rot, and cotton wool disease.

  1. API Aquarium Salt

This is the number one salt for freshwater aquariums. It is manufactured by a reputable company –Aquarium Pharmaceuticals Inc. (API) – and it is regarded as the best professional aquarium salt for freshwater tanks. 

When added occasionally to freshwater tanks, this salt promotes fish health and heals fish suffering from common fish diseases such as gill rot and tail rot. 

It is also designed to improve gill function and add electrolytes to water.

The best thing about this aquarium salt is the fact that it can be tolerated by many freshwater fish species when used sparingly. 

And the second-best thing about it is the fact that it is made by evaporating seawater. So it is very pure and all-natural.


  • It is a great freshwater salt product
  • It works brilliantly
  • It is pure and natural 
  • It treats common fish diseases


  • It has no cons 
  1. Seachem Brackish Salt

This salt is best for brackish tanks with brackish aquarium fish such as moonies, guppies, mollies, and mudskippers. 

The salt is made by Seachem and it is perfect for replicating the real environment brackish fish live in.

It is also great for routine use in freshwater aquariums to prevent diseases. 

The best thing about it is the fact that it is safe for routine freshwater tank dosage.


  • Made by a renowned manufacturer in the U.S.A
  • Perfect for freshwater fish 
  • Great for brackish fish 
  • Very effective


  • Not very cheap 
  1. Instant Ocean Sea Salt for Marine Aquariums, Nitrate & Phosphate-Free

This aquarium salt is one of the best-rated and best-priced aquariums on the market. It is perfect for brackish fish and for creating marine aquariums. It is also great for purely freshwater tanks

The best thing about it is that it is very pure and very safe. This is perhaps the reason why it is the world’s number 1 sea salt.

The second best thing about it is the fact that it dissolves very quickly. You don’t have to mix it with water before adding it to your aquarium.


  • Made by Instant Ocean
  • It dissolves fast 
  • It is great for clearing cloudy water
  • It does not affect Ph
  • It has no additives


  • It is a bit pricey compared to similar products


Table salt is strictly for humans. The salt for fish is aquarium salt. Compared to table salt, aquarium salt no additives that are harmful to fish. Aquarium salt is great for both saltwater and freshwater fish. The benefits include better immunity and a lower likelihood of suffering from fungal diseases. The best aquarium salts on the market particularly for freshwater tanks include the API Aquarium Salt and the Seachem Aquarium Salt.