· Their maximum life span is about 200 years in exceptional cases. Normal life span is more like 25 to 35 years if cared for properly.
· Their maximum length is about 3 feet depending upon blood line and proper care.
· Koi have no stomach, but have a straight gut. In warm water, koi will digest their food in about 4 hours. For maximum growth, they should be fed what they will eat at 4 hour intervals.
· Koi will eat many things; however it is best to feed them a well-balanced koi food, containing at least 30% protein.
· The value of a koi mostly depends upon size, pattern, and color. Realistically, a koi is only worth what someone is willing to pay.
· Koi can withstand a wide range of temperatures and pH values; however a rapid change in either value can cause undue stress and many times will cause death. (Water temperatures from 45º F to 90º F, and pH from 6.5 to 9.0)
· Koi ponds should have areas that are at least 3 feet deep for koi to hibernate in winter, and should have some shade so they will not sunburn (in very shallow water) in summer.
· Koi are "schooling" type fish that desire to be with other koi. To keep your koi content, always have more than one koi in your pond or tank.
· Koi continually excrete ammonia into their surrounding water. If the ammonia level is allowed to become excessive, koi can no longer excrete their waste ammonia and can die from ammonia poisoning. Do not over crowd your pond with fish, and do not over feed. Either condition will add ammonia to the water. A good biological converter will absorb the ammonia and keep your fish healthy.
· Koi get oxygen from the water through absorption in their gills, where oxygen is absorbed directly into their blood stream. Pond water should be kept well oxygenated all year by waterfalls or other forms of aeration.
· Koi Produce thousands of eggs during spawning season. Male fish fertilize the eggs by spraying the eggs with milt. If the eggs are laid in an open area, they are quickly eaten by the other koi. Baby koi will hatch in 3 – 7 days depending upon water temperature. Less than 50 percent will survive.
· Koi get along well with other species of fish, as long as the other fish are not aggressive. Koi will eat their young until the fry show some color on their bodies.
· After transporting koi to another location, float their water bag in the new pond or tank about 30 minutes to equalize water temperature before releasing them. Do not pour water from the bag into the pond or tank. This is a bad practice and can spread disease and/or parasites.
· Most koi have some parasites. Most parasites are microscopic and cannot be seen without the aid of a microscope. A trained specialist can examine your fish and determine if your pond or fish should be treated to eradicate parasites.
· Know the water volume of your pond. Koi can be placed under undue stress and sometimes die because the pond owner over dosed their pond with medication algaecides, or other additives. It is important to know the pond water volume when applying these additives. Proper concentrations will generally not cause undue stress to the fish.