AS A FRESHWATER HOBBYIST, you probably don't find salt on your shopping list very often. But salt actually has a number of beneficial uses in the freshwater aquarium. Made from evaporated seawater, freshwater aquarium salt can reduce stress, treat some external parasites, and protect fish against the effects of nitrite spikes.

reduce stress
During times of stress or when fish are diseased, their gills may not function efficiently. As a result, fish can experience osmotic shock, by which electrolytes are lost through the gills, impairing the fish's ability to take in oxygen and release carbon dioxide. Freshwater aquarium salt contains beneficial electrolytes that replenish the electrolytes lost during these times of stress or disease, resulting in improved gill functioning. For this application, add one tablespoon of salt for every 5 gallons of water or per manufacturer recommendations.

treat parasites
Freshwater aquarium salt can serve as a short-term bath treatment for freshwater external parasites such as Tricodina, Ichthybodo, and Epistylis. For this application, dissolve 2-1/2 cups of salt for every 10 gallons of water in a separate container. Carefully place the infested fish in the container for 5 to 10 minutes, and then place the fish back in tank. Repeat in 24 hours if necessary.

protect fish from nitrite poisoning
When water quality is compromised and nitrite spikes, freshwater aquarium salt can help temporarily block the toxic effects of the high nitrite levels and protect your fish until water quality improves.

hatch brine shrimp eggs
Brine shrimp are an excellent food source for many fish, but require brackish water to survive. By adding freshwater aquarium salt to RO water, you can increase the salinity level of the water to achieve brackish conditions. Add eight tablespoonfuls for each gallon of water until you achieve a specific gravity of 1.005 and 1.015 SG. Remember to hatch brine shrimp outside of the aquarium in a separate container as brine shrimp eggs can kill small fish that are unable to digest them.

considerations for use Restrict salt use in freshwater aquariums to aquarium-specific freshwater aquarium salt, not iodized table salt. Freshwater aquarium salt is specifically designed to benefit your aquarium, and does not contain any artificial additives or sugars, nor will it raise pH or affect water hardness. Table salt can contain ingredients that may be harmful to your inhabitants or negatively affect water quality. The use of freshwater aquarium salt is not recommended for some planted aquariums or aquariums that house some scaleless fish, such as Corydoras, because certain plants and fish are extremely sensitive to salt. Freshwater aquarium salt is also not a substitute for marine salt because they are designed for very different purposes.