Laguna Koi Ponds

(949) 494-5107


Library Heat Therapy

Laguna Koi Ponds
20452 Laguna Canyon Rd.
Laguna Beach, CA. 92651 U.S.A.
Hours of Operation:
Monday-Friday 9AM-5PM Satuday 10AM-5PM
Sunday 11AM-4PM
(949) 494-5107
Pond Calculator App for Android

Heat Therapy

Koi are not truly a cold water species. Although they can live in very cold water, their metabolism functions better when the water temperature is near 76 degrees Fahrenheit. Koi's immune system is very slow below 65 degrees Fahrenheit. Many Koi ponds throughout the world never reach prime temperature for Koi.

Heating a pond may not be practical or economical. However, an indoor tank, complete with heater and filter system is within most hobbyist's grasp. When a Koi is weak or diseased he can go into heat therapy with or without medication. Bacteria, viruses, and parasites all cure more quickly when the koi's immune system is functioning properly. In essence, this is what happens when people get a fever, it is the warm blooded animals natural response to activate the immune system. Koi, being cold blooded, do not have this advantage.

We have maintained an insulated room with 8 warm tanks at Laguna Koi Ponds for three years now. Most Koi respond very positively to the warmer water.

Viral infections like lymphocystis (white globular growths) can be cured at 80 - 84 degrees. Viral diseases are only treatable by the fishes natural defenses.

There are no effective medications.

Bacterial diseases like Aeromonas, "hole in the side", mouth rot, etc. are often cured without any antibiotics at 80 - 84 degrees Fahrenheit. In this situation, a combination of factors are in effect; the Aeromonas bacteria does not live well in elevated temperatures and the koi's immune system is very high. The most severe cases do receive antibiotics incorporated into the food. Salt at 0.3% - 0.5% (2.5 - 4 lb. / 100 gallons respectively) is usually maintained during therapy. Recovery is rapid (1 - 3 weeks).

Some cases of bacterial dropsy (bloat) have been cured. Koi which receive too much pellet food in the winter can become congested and acquire bacterial dropsy symptoms. Food is not being digested at low temperatures and begins to ferment. The body bloats and the scales will protrude and show bleeding (a pine cone effect). Heat therapy gets the digestive enzymes working. Feeding with a medicated food in warmer water has cured some cases of dropsy. This can be a difficult disease to treat due to its complex nature; early treatment is necessary and heat should be considered. However, depending on the actual disease organism, heat therapy can speed its growth and kill the Koi sooner. A better method would be to raise the temperature very slowly to only 70 degrees and initiate antibiotic therapy with salt at 0.5%.

Parasites will be treated more quickly in warm water. Weak Koi will gain vitality and strength, and will have an enhanced ability to cope with the parasitic infestation. Some parasites are encrusted on the Koi and chemical treatments are ineffectual. Warm water speeds up the parasite life cycle, releasing the cysts allowing the medication to kill the subsequent free swimming "spores".

Do not raise the koi's water temperature too fast. Parasites and bacteria can also grow more quickly in warm water. The fishes system takes time to adjust but the disease organisms do not. Raise the temperature from ambient at 3 - 5 degree intervals every 24 hours to 80 - 84 degrees Fahrenheit. Maintain a stable temperature with less than 2 degrees variable per day Treat with 0.3% salt and parasiticides or antibiotics during the adjustment period, and continue with medication if necessary until cure is affected. Maintain temp. for 4 - 6 weeks after cure, then slowly drop the temperature to match that of the pond water. This will ensure a stronger Koi and ease the fishes transition back to the pond.

We would highly recommend serious hobbyists use a heated tank for medication purposes. Heater wattage should be approximately 2 to 3 watts per gallon. Aquarium style heaters work well with submersible or non-immersible types available. Use as large a treatment tank as possible. Try 40 gal. plus for small 6" Koi, and 100 gal. plus tanks are required for larger fish. Always provide an established biofilter so waste products do not accumulate. Stability of all environmental factors is the key.

Give heat therapy a try! Your Koi will warmly thank you.