Pond Boss Forums INTRO Questions & Observations Koi?

Koi are ornamental common carp developed hundreds or maybe thousands of years ago for their color. My koi book says 2,500 yrs ago and they originated in several eastern Asia seas and China. Records of them are from 400-500BC! Although highly colored versions appeared around 200 yrs ago. Koi were first introduced to Japan by invading Chinese. Koi keeping is a big time hobby now.

They feed like common carp. They are omnivorous which means they eat a variety of living and dead plants and animals. Most of their diet and protein source is from benthic invertebrates. They root into the sediment up to their eyes digging, sucking and straining out food materials.

Their barbels or "wiskers" (they have four two on each corner of the mouth) contain lots of very sensitive taste buds. Thus they can taste the food before gets into their mouth. Lips and fleshy mouth also contain many taste buds. Nostrils (four in all) with smelling cells also allow them to smell food odors in the water even from distant objects. Sense of smell is more important to them than eyesight for finding food.

Some of their diet is algae or soft plant material, but it amounts to only about 10%-25% other their diet. If one gets any plant/algae reduction from koi it is due to primarily their roto-tilling or rooting of the sediments. They are basically aquatic pigs or hogs. This disrupts plant life and roils the water thus causing a suppressive effect on bottom plant life. Digging action also uproots shallow rooted plants. The more of them you have the murkier your water becomes. This cloudy water is not a plankton bloom, it is suspended mud/clay/ organic particulates in the water.

PS. He was crusing just below the surface in the layer of warmest water; sort of like sunbathing. Grass carp/amur often exhibit the same behavior.
About the only predators a 19" koi has are you and an alligator.
They are fertile and will easily breed with wild carp since they are the same species.