Before you go about using the same care and maintenance routine as last year, koi enthusiast Tom Holder, president of Koi Care Kennel Inc., has some upkeep advice. Koi Care Kennel provides products to help maintain a healthy living environment for koi and Holder has been working with koi for 15 years.
“Water quality doesn’t always matter. Ninety-nine percent of dead fish are caused from pathogenic bacteria and parasites,” Holder said. Aeromonas, a type of microscopic bacteria, is the biggest threat of all the bacteria that is living in your pond.
Aeromonas decompose the flesh of koi and feed on the nutrients in the koi’s waste.
“Control fish waste and you control aeromonas,” Holder said, as he referred to koi ponds as “closed, recirculating toilets” in terms of waste excreted by the fish. Holder’s best advice for getting rid of these bacteria and the waste they feed on is to “flush the toilet.”
A combination of frequent water changes and proper filtration will help prolong the life of your koi. Filtration should occur through a bottom drain and the floor of the pond should be free of rocks.
According to Holder, rocks placed at the bottom of the pond will collect waste in the crevices, which eventually leads to buildup of bacteria.
Though bacteria can never be fully expunged, koi use their outer slime coat to fight off harmful microbes and can live with low levels of bacteria in their habitat.
Bacteria can be the most harmful to the koi, but only if the slime coat is compromised by parasites. Measuring 100 times larger than bacteria, parasites penetrate and open the slime coat and allow bacteria to directly affect the fish, Holder said.
A phenomenon that recently has developed in the koi world is embedded parasites, which are harmful to the health of the koi.
“Once parasites are embedded in slime coat they cannot be harmed by any products that you place in your pond designed to kill them,” Holder said.
Holder recommends treating your pond for parasites using parasite products, such as Koi Care Kennels Koi PraziPond Plus, every three to four months for two years. A new two-year cycle of treatments must be started each time new fish are introduced to a pond and treatment before winter is best, Holder said.
Here are some additional tips from Holder and Better Homes and Gardens on how to care for your koi during the summer.
• Try to avoid using salt as a therapy for koi. “You’re never going to kill a parasite today using salt,” Holder said. It might calm the koi down temporarily, but it thickens the slime coat and increases the survival rate of embedded parasites.
• Change your water in small amounts because water changes can make temperature vary, forcing the koi to adapt to an ever-changing environment and can be detrimental to their health. Ideal water temperature is 77 degrees.
• Using pH control products can also be harmful to the koi. The pH products will cause pH levels to go up and down temporarily. When the levels change the koi are forced to adapt, which eventually can make them sick.
• During summer months, heat levels rise causing oxygen deprivation. To make more oxygen available to the fish, install some type of moving water, such as a waterfall or fountain. If you are unable to install a moving water source, frequent water changes will give your fish more oxygen.
• Keep an eye on water levels because water evaporates quickly during the summer.
• Koi food needs to be low in protein and the optimal time to feed is during the cooler times of day.
• As a general rule, use 10 gallons of water for every one inch of fish.