Adding salt to your pond helps your fish grow

May 09, 2009|By JEFF RUGG / Creators Syndicate

Q: We have a koi and goldfish pond with a few plants in it. We have heard that we should add salt to the pond, but we are unclear about how much is OK, how much is too much, what it does and whether it will hurt the plants.

A: Let's cover the reason why first. The fish's body is saltier than the water in the pond. So, water wants to even out the two different salt levels to one average level. The fish have to expend calories to keep salt in and water out of their body. They have a slime coat, scales, gills, kidneys and skin all trying to keep the water out, but they are constantly breathing and swallowing water in. This energy could be used for growth, immune system work, etc., if the water were saltier.

If you see a fish that is inflated like a balloon and the scales are all sticking out at right angles from the body, you see a fish that is drowning. It may have any number of diseases or other problems, but by the time you see the scales sticking out, it has kidney or gill failure and it cannot get rid of the water buildup in the body.


In a typical goldfish pond, 1 pound of salt per 100 gallons of water will benefit the fish without harming anything else. Ten pounds of salt per 100 gallons of water is used as a dip for a few minutes at a time. Koi and goldfish are very tolerant of salt. I once did the wrong math and had 10 times the salt in a salt dip tank and the fish immediately keeled over in the water and could not maintain their balance. I pulled them out after 10 to 30 seconds and placed them in unsalted water and they showed no ill effects.

Raising the salt level in the pond to 3 pounds per 100 gallons over a week or so will potentially get rid of many parasite problems. This practice is often recommended first thing in the spring or when new fish are in quarantine before adding them to the pond. Keep the salt level at 3 pounds for about three weeks and then slowly decrease it back down to 1 pound or to zero. In a pond with a functioning biological filter, there may be a dip in the population level of the bacteria if the salt is increased too fast. During those few days, the ammonia or nitrite level could spike up to dangerous levels. If you overdose the salt, just remember the old adage: The solution to pollution is dilution.

Most water-garden plants and other animals like frogs, snails and such will not be harmed at all by the 1-pound rate. The 3-pound rate will slow the growth of some plants and may kill some plants that float in the water, but it is not a good algae control method.

The best salt to use is kosher or pickling salt. It must not have any anti-caking ingredients like yellow prussiate of soda that are toxic to fish. Solar and water softener salts are not the best to use.

Q: I have been given some canna roots that were extras from a neighbor's flowerbed. I have used as many as I can and was wondering if I could save some until next summer. How would I go about it?

A: While it is generally possible to save both summer bulbs and winter bulbs for more than a year, it is not a good idea. Many types of plants have a storage area in the roots or stems called a bulb, corm, rhizome and a few other terms, but none is designed to last for more than a year. In nature, only a few desert plants don't get good growing conditions every year.

I have an amaryllis bulb that I left in a pot for a year and a half without sun or water and it shriveled a little at a time until there was practically nothing left. It looked fine on the outside because the dried scaly bulb just sat there while it dried up on the inside. I repotted it and started watering it, and it has a couple of leaves, so it looks like it will survive, but it will be a couple of years before it blooms again.

You might get canna roots to survive if you keep them cool, dark and dry, but they will probably dry up and die. You might get 10 percent to live, but since it will take so long to get them to bloom again, it won't be worth the effort and they will probably just get thrown out.

Since they were shared with you, why not keep sharing and give them to another neighbor? Many nonprofit organizations have very low budgets and would love for someone to plant some flowers around their sign or near their front door.

In these hard economic times, if it is possible for you, why not plant a few extra flower pots and donate them to nonprofit groups to beautify their surroundings? Plants and blooming flowers have been proven over and over again to make people happier and think more positively about themselves, so give it a try.

E-mail questions to Jeff Rugg, Kendall County unit educator, University of Illinois Extension at

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