Is Aquarium Salt Necessary in My Freshwater Tank?

Non-iodized mineral salt--sometimes sold commerically as "aquarium salt"--can sometimes be a useful addition to a saltwater aquarium. But while there are some benefits associated with the conscientious use of aquarium salt, the practice may be dangerous to fish and live plants. Aquarium salt is generally unnecessary for freshwater fish.

  1. Types

    • Aquarium salt differs from the form of salt used in saltwater fish tanks. Typical aquarium salt is simply non-iodized table salt (sodium chloride) with no other compounds or ingredients. Saltwater fish require ocean-sourced marine salt, which contains natural trace minerals like magnesium.

    Benefits

    • Aquarium salt can improve tissue healing, slime coat production and kidney function in freshwater fish. Aquarists may also use salt to eliminate parasites or prevent nitrate poisoning.

    Necessity

    • Brackish-water fish like gobies, mollies and green spotted puffers require the use of marine salt or aquarium salt. However, true freshwater fish thrive without aquarium salt and do not benefit from its routine use.

    Warning

    • Aquarium salt, especially when used in moderate to large amounts, can kill scaleless fish like corydoras. Snails and plants can not generally tolerate salt in a freshwater tank.

    Alternatives

    • Most benefits associated with aquarium salt can be acheived through "stress coat" products. These do not harm plants or scaleless fish.