Salting The Koi Pond: How Much Salt Should Be Added?

Last updated on October 23rd, 2023 at 08:33 pm

If you want to enrich your garden pond with koi, you will find the noble fish with the iridescent scales in a salt tank in specialized stores. Coincidence? No, salting the koi pond is considered a secret care tip. Even professional breeders from Japan, the country of origin of the fish, recommend adding salt. What are the benefits of salt in the koi pond? And what is the correct dosage for the species?

Salting The Koi Pond: How Much Salt Should Be Added?

Positive effect of salt

  • Prevention of algae formation
  • Stress reduction of the fish
  • sliming and flushing of the gills
  • increased energy metabolism of the fish
  • faster recovery of fish after diseases
  • faster recovery of fish from long transports
  • Salting up for regeneration in case of dropsy

At the first signs of dropsy, the addition of salt to the koi pond serves as a first aid. Often this form of treatment is the only natural therapy to avoid medication. However, if the owner is already administering medication, he must not increase the salt content under any circumstances. The combination causes serious interactions.

Not only diseased koi benefit from a short-term increased salt concentration of the water. The addition creates an osmotic pressure. Here, the salt content of the water is higher than that in the fish body. This leads to a salt withdrawal of the fish body. The animals gain new vitality as a result. Especially after a cold winter, the owner can enjoy increased vitality of his fish with this method. Warmth additionally strengthens this effect. The following instructions should be followed:

  • Prepare quarantine tank
  • Increase water temperature by 1 to 2°C
  • Increase salt concentration to 0.5 to 0.6

Note: For the treatment of diseased fish, the keeper should not salt the entire koi pond. If possible, therapy should be carried out in a separate quarantine tank and should last no longer than three to five days

Salt koi pond against algae?

Salt in the koi pond prevents the formation of algae. However, the owner should not exceed a dosage of 3 kg per 1000 liters of water. Contrary to what many people believe, the addition of salt does not help with parasite infestations. There may be a short-term improvement in the health of the fish, but the actual cause cannot be eliminated in this way. It should also be noted that an increased salt concentration is detrimental if the breeder is already administering potassium permanganate against fungal infestation.

Different types of treatment

The duration of salting the koi pond depends on the purpose of application. Breeders distinguish between three different options:

The short-term bath

Duration: about 20 minutes
Salt concentration: 1.5 to 2%.
Effect: slime removal, formation of new mucous membranes
The permanent bath

Duration: 3 to 5 days
Salt concentration: 0,2 to 0,5 %.
Effect: stress reduction after long transports, reduction of nitrite levels
The permanent bath as a therapeutic bath

Duration: 3 to 5 days
Salt concentration: 0.5 to 0.6%.
Effect: recovery from dropsy, promotion of wound healing

Type of salt

In no case the holder use iodized salt. Iodine causes severe damage to the gills of the fish. Instead are suitable:

  • iodine-free table salt
  • Sea salt
  • Pond salt
  • livestock salt

Note: Special salt is also available in hardware stores. However, the purchase is not worthwhile, since conventional table salt is in no way inferior to this product. However, there may be a price advantage because special salt is sold in larger packaging quantities


The dosage should not be done by eye, but always with caution. Too high a salt content is not only detrimental to the health of the koi but also to the aquatic plants. Breeders recommend the following dosages depending on the planting of the garden pond:

Koi ponds with planting: 1.5 kg per 1000 L of water.
Koi ponds without planting: 3 kg per 1000 L water
Sick koi should be treated by the keeper with less than 2 kg per 1000 liters of water.

Note: Although salting a koi pond has a positive effect, the treatment should not last too long. Koi are not saltwater fish and sooner or later will urgently need fresh water


  • prepare quarantine tank
  • Be sure to install an aeration source (salt deprives the water of oxygen).
  • determine the salt content of the pond with a test device from the hardware store
  • ladle water from the koi pond into the tank
  • Do not dissolve salt, but add it directly to the pool
  • Put koi in the basin
  • cover with a cloth as a precaution (fish may try to jump out of the narrow basin)
  • as soon as a koi swims on its side, stop treatment immediately
  • put koi in fresh water after 5 days at the latest
  • first prepare a freshwater tank
  • let the koi swim in it for 20 minutes
  • only then put them back into the pond


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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