Is It a Good Idea to Add Salt to a Koi Pond?

Koi don’t generally live in saltwater habitats even though they’re known to survive in brackish water, but not for long. Some carp species used for sustainable aquaculture such as rice-fish farming can handle a higher level of salinity. However, these fish have been selectively bred for symbiotic purposes. Ornamental koi are strictly freshwater species, but this doesn’t mean they should be stocked in a garden pond filled with pure water. Pond keepers are responsible for regulating water chemistry, and this includes providing some salinity for the benefit of koi and other species. The staff at Aquatic Warehouse, a leading provider of koi pond supplies, would like to share some details on whether salt should ever be added to a koi pond.

The Use of Salt in Koi Farms

At koi harvesting facilities, breeders manage mud ponds for the purpose of raising healthy fish. In the aquaculture practice of raising edible carp, mud ponds are also preferred because of organic benefits. When koi grow past their juvenile stage and turn into ornamental fish, they’re transferred from their native mud habitats to tanks. The processes of handling and transporting fish are stressful, which results in a release of hormones into the water, thus causing an osmotic imbalance that can be counteracted with salinity.

Osmotic Regulation

When you acquire koi to stock your pond, the fish have likely been put through an osmotic regulation process facilitated with salt. Similar to humans, koi stay healthy by means of keeping adequate sodium levels. When switching from mud ponds to tanks and ultimately to garden ponds, koi accelerate their breathing process, causing sodium and ion depletion. Breeders treat tank water with small amounts of salt, no more than 0.75 percent, to help koi reach an adequate osmotic balance, but the salinity will be lowered to a minute amount after a few days through water changes before offering fish for sale.

Salt as a Healthcare Treatment for Koi

If you hold a koi fish in your hands, you’ll feel that it’s slimy. This is often the case with other aquatic species as well, and it’s because of mucus secretion. The natural immune systems of many fish are augmented by mucus, and salt acts as a stimulant in this regard. Some plankton parasites are also mitigated with the use of salt in pond water. There’s a reason edible fish taste salty even when caught in freshwater habitats. The concentration level of salt in fish blood can be as high as 1 percent. Healthy koi regulate blood salinity to 0.9 percent.

When Salt Shouldn’t Be Used in a Koi Pond

Assuming your pond ecosystem is healthy, you don’t need to add any salt, particularly if your koi were raised in tanks with proper osmotic balance. You may need to add salt when treating a pond with high concentrations of Costia parasites, which cause koi to become lethargic, isolated, and overly coated with excessive mucus. Instead of adding cooking salt, it’s better to use a pond water treatment specifically formulated to eliminate Costia. Follow the treatment instructions carefully because you may need to perform a couple of water changes after dosing the pond, and it’s best to use a digital meter to be accurate.

When caring for a koi pond, there are several things you’ll need to acquire to keep your fish happy and healthy for many years to come. For all of your essential pond equipment needs, reach out to Aquatic Warehouse. Stop by our store in Kearny Mesa, order everything you need from our website, or give us a call at 858-467-9297 with any questions you might have.