The Benifits of Salt

Salt use in Koi Keeping

Even though Nishikigoi are fresh water fish there are several benefits to adding small percentages of salt to their environment. By small I mean 0.25 to .3 % for long term use, 0.5% for short durations of a few days and up to 2% for just a few minutes as an anti-parasitic dip treatment. First we’ll go into the reasons for using salt then we’ll look at how to use it safely with your koi.

1- Even low levels of salt reduce osmotic stress levels. Osmotic stress is caused by water passing through the skin and gill tissue. A koi’s organs must remove excess water to maintain proper internal fluid levels. To understand why salt is beneficial to this process think of a koi as an organism with a finite amount of total energy. This finite amount of energy must be allocated to certain things to keep the koi healthy and flourishing. Some of these include energy for movement, growth, reproduction, the immune system, stress responses, and osmotic regulation. If a Koi is stressed by external factors it will have to use energy to combat the effect of stress to try to remain healthy or to just survive. This results in less energy for the things that we as koi hobbyists are most interested in, the immune system and growth. There are things we can do to reduce external stresses, the major one being maintaining water quality. If ammonia and nitrite levels are kept as close to zero as possible by your bioreactor and nitrate and dissolved organic carbons are removed through regular water changes that energy will go where we want it. Adding salt to the water has a smaller effect than overall water quality, but it is an easy way to create an energy excess by reducing the amount of energy that goes to the process of removing excess water from the tissues. Since koi live in water they are in a constant battle to remove excess water from their bodies while retaining vital minerals and SALTS. By adding salt to their environment we make the outside chemistry closer to what is inside of the koi’s tissues. This lightens the load on the organs producing the desired energy excess. This is why sick or injured koi are placed in salted water. They need all the energy they can muster to fight infection or to heal a wound.

2 - Fresh water parasites will not tolerate salt. The majority of parasites that end up on your koi can be killed off by adding salt to .3%. In some cases a level of .5%-.6% may be necessary to take out some of the nastiest flukes, but a good retailer should have checked for infestations before releasing a koi for sale to you. If you can’t keep your pond salted it is possible to use salt in a short term dip treatment. We’ll cover how do a dip later.

3 - Salt reduces the toxicity of nitrite. A bacteria colony supported by a bioreactor processes fish waste from ammonia to nitrite and then to nitrate. Ammonia and nitrite both have toxic effects to your Koi. If your bio system is undersized or not functioning well these toxins can quickly build to dangerous levels. Ammonia can be bound with many different water conditioning products or binders. These compounds change ammonia to ammonium which is not toxic. Be aware the most test kits will show total ammonia - both ammonia and ammonium, so you will still indicate ammonia levels after treating with a binder. There are no binders for nitrite, it can only removed by bacterial conversion or water changes. Until you can get you bioreactor up to speed do multiple water changes and add salt to lessen the toxicity of nitrite. Keep in mind when doing water changes, a dechlorinator must be used as even low levels of chlorine can be harmful to gill tissue. Feedings should be kept to a minimum to keep from adding more ammonia and nitrite to an over loaded system.

4 - Effective use of salt. First, the salt you use must be pure sodium chloride with no binding agents. Binding agents are used in making water softener salt into uniform pellets. Do not use any product with potassium or iodine. The most economical source is Morton's Water Softener Salt in 40lb BLUE bags. It contains pure sodium chloride salt in rock form without anything unwanted and is only about $5 a bag at home centers.

Salt can be used only in quarantine tanks or in your whole system. When you decide to add salt to your pond you have to make a choice between most plants and koi. If your main focus is on the plants of a watergarden this is not for you. If you’re more into koi but still want some plants the cheaper plants seem to tolerate slow introduction of salt better than say a $50 Lotus. Lower levels may still be beneficial and will do less harm to plants.

- 1 lb of salt per 100 gallons of yields a concentration of .125% / 1.25 parts per thousand
- 2.5 lbs of salt per 100 gallons yields around .3% / 3 parts per thousand concentration.
***To find total volume = length x width x average depth x 7.48(gal per cubic ft)
round ponds total volume = radius x radius x 3.14 x average depth x 7.48

Don’t forget to add the volume of water in your filter, bioreactor, and if it is extensive your plumbing system.

Obvious flaws are introduced with this technique. No pond is a uniform box. This method is fine though as even a large percentage overdose will not harm your koi.
Exact volume totals are much more vital for other medication and can be found by using a flow through meter on a hose when the pond is filled from empty. The best way to get accurate salt levels is by using the Koi Medic Salt Meter. It measures level from 0.01 to 1 percent or in ppt. It is a very quick and easy to use meter which requires no calibration.

To add the salt, mix a few pounds at a time in a 5 gal bucket and pour the solution in around the perimeter of the pond. Avoid large quantities close to the koi and never put any kind of treatment or chemical directly into shimmer or filter intakes. Do not put raw undissolved salt into the water. Add the salt 1/3 of the total dosage at a time over at least 3 days if not 5. For sick fish in quarantine add it in one to two days.

5 - Dips can be used to treat a known parasite problem when required or at regular intervals as a preventive measure. One cycle in the spring and again in the fall should be more than enough to keep most bugs well in check. 50 tbls of salt in 5 gallons of pond water will do the job. Immerse the koi in the dip for no more than 5-7 minutes every other day for 3 total treatments. If the koi shows signs of distress like very labored respiration, or rolling onto it’s side remove it to fresh water immediately. Smaller koi will tolerate the treatment for only short periods of 2-3 minutes. Watch them closely and don’t go for the home run with this treatment. Reasonable duration over multiple days is safest and works well.

That covers salt usage in the Koi hobby. While a continuous level of salt may not appropriate for everyone, keep some of these methods in mind. Salt for sick fish in quarantine systems or as a dip are easy, low cost treatments that anyone can employ without fear of harming your koi.

Rick


References-
Associated Koi Clubs of America Koi Health Advisor (KHA) course material

Advanced Koi Care, Nick Saint-Erne DVM

Koi Health and Disease, Erik Johnson DVM