Winter Season Tips

Winter Koi Keeping Tips

If your Koi are remaining outside:
1) You must maintain an opening in the ice for oxygen to get in and carbon dioxide and other toxins to escape. There are two ways to do this. First is with a stock tank or pond heater, which does the job, but consumes a lot of power without adding oxygen. The second possibility is with a moderate volume pump and a high quality airstone. This method adds oxygen all season long, thus keeping your Koi alive. More importantly it helps to prevent the debris in the pond from becoming anaerobic. This is the breakdown of organics in the absences of oxygen which results in the production of hydrogen sulfide gas, a highly deadly toxin to Koi. If you have ever removed detritus from a filter or stagnant area of your pond and smelled rotten eggs, that is what we are talking about, Very Bad Stuff!
Try not to use a high volume pump (i.e. 40Lpm or more), as you don’t want to churn the water which will destratify the water column and reduce the temperature. Just enough the keep the air flowing is good. A large volume aquarium pump will do, however most are not rated for outdoor use so they will need protection from the elements. Jamie Beyer of Midwest Aquascapes suggests elevating the pump on a brick or rock and covering with a large Tupperware container or bucket.

2) If possible, shutdown or bypass streams and waterfalls. Their operating during cold weather will keep the ice open, but also super cools the water by exposing more moving surface area to the cold. The result is a lower temperature than would occur if the ice was frozen solid, thus forcing your Koi to endure much lower temps. The result will be more winter kills and more disease problems in the spring due to elevated stress levels throughout the winter.

3) Maintain flow though your bio-converters. Nitrifying bacteria becomes ineffective below about 50 deg F, but does not die. It merely goes into a hibernative state. Once temps return to the 50s and food becomes available the colony of bacteria becomes active. If you do not maintain the health of you bio-converter you are beginning the startup process a new each spring, inducing high levels of disease causing stress.
If this is not possible, place a portion of your biomedia in the pond next to the airstone to preserve the colony, or bring the media inside to an aerated tank or trash can. A couple of your smaller goldfish in the tank will sustain the colony.

4) Keep as much debris as possible out of the pond before ice over. Detritus on the bottom harbors parasites and anaerobic bacteria previously discussed.

If your Koi come inside:
1) Provide adequate established bio-conversion. This means having a filter setup with lesser fish providing waste at least 4 weeks prior, 6 weeks preferred.

2) Monitor ammonia, nitrite, and pH closely!!!! The very small volume of water allows quality parameters can "go south" very quickly. Ammonia and nitrite should be as close to undetectable as you can keep them. Ammonia becomes less toxic at lower temps and lower pH. If any ammonia is present it must be bound with Amquel, Prime or similar product prior to raising the temp or doing a water change (see #3). Nitrite toxicity is reduced with salt (see #4). pH levels can drop rapidly in a stock tank or EPDM liner tank. Maintain elevated alkalinity, thus stabilizing pH via weekly 10-25% water changes.

3) You must do weekly 10-25% water changes to ensure stable water quality. Prior to adding water treat for existing levels of ammonia. Adding tap water of high ph can raise ammonia toxicity rapidly. Des Moines’ pH on November 25th, 2008 was in excess of 9.0. Raising a closed systems pH by 1.0(i.e. 7.0-8.0) raises the toxic effect of ammonia by a factor of 10! On the other side equation is an established bioconverter. The process of nitrification releases acids into the water, thereby counteracting the tap pH over time.
Is your water treated with chlorine (as Des Moines' is) or chloramine? Some of the suburbs of Des Moines are treated with chloramine. If your residence is a great distance from the treatment facility, it's a good chance that your water is treated with longer lasting chloramine. Chloramine is a combination of chlorine and ammonia. If you treat chloramine with only a chlorine remover (i.e. sodium thiosulfate) you are releasing ammonia into an environment in which you are trying to remove it. Again, Amquel, Prime or similar duel purpose treatments handle this problem. For straight chlorine it’s often more economical to use a product like Vanish to remove just the chlorine.

4) Add salt @ 3 lbs per 100 gallons. Add 1/3 of the total per day over a 3 day period. This level (0.3-0.4%/ 3-4 parts per thousand) should be maintained for a period of 3-4 weeks to cover known parasite life cycles, and then be allowed to fall through routine water changes.
Benefits are numerous!!!!!!
a- reduces nitrite toxicity
b- kills and prevents the life cycle of a great number of parasites. You can use this time as a yearly period to reduce the effects of common parasite infestations.
c- reduces osmotic stress, providing an energy surplus which can then go to the immune system to fight disease and infection, or to increase growth rates. Koi’s kidneys are in a constant fight to remove water from their systems. If the water’s salinity is closer to the Koi’s internal level of .9%/ 9 ppt then the resultant stress on the internal organs is reduced. Many experienced hobbyist maintain some level of salinity all the time for these reasons.

5) Control temperature variations. In some instances the over winter location is in a garage or out building. Daily temperature fluctuation of more than 5°-10° F are stressful. Koi’s internal organs and metabolic rates are regulated by temperate specific
(+or- 20° F) enzymes. It takes several days to fully transition from one set of enzymes to another, again inducing stress and suppressing the immune system. Avoid a temp range of 47°-62°F, because in this zone the Koi’s immune system is basically nonfunctioning but certain infectious bacteria are still active. These bacteria are the ones responsible for mouth and tail rot, and open sores or ulcers seen mostly in the spring as the pond transitions this temp zone. Try some of the following:
a- Stock tank heaters. They can be costly to operate and most shut off well below 50°F. Look for units with a higher temp range.
b- Large wattage submersible aquarium heaters. Again can be a little costly to operate, but can be set to a specific temperature. Care should be taken to keep Koi from snuggling up to the heat source and possibly causing burns and large Koi are capable of breaking the glass of aquarium heaters. Try to isolate the heat source in some way if this becomes a problem.
c- To help retain the heat, wrap the tanks with fully incased, formaldehyde free batting insulation (Johns-Mansfield). Even more important is to retain heat at the surface. Covering all or a portion of the tank with pink board insulation works great. Covering the tank 24 hours a day may not be required, but at least over night when temps are lowest.

6) If you don’t use the pink board you will need some form of lid. Koi moved from one location to another WILL JUMP AND YOU WILL HAVE LOSSES!!! A PVC electrical conduit frame with leaf netting works well. It is light weight and non-injurious to the Koi.

Hope you find these helpful. You can see an example of one of our tanks in the Learning Center.

Rick