Kohaku Koi — Variety Guide

Kohaku — one of the 12 koi varieties owners look up by name.

Kohaku Koi — photo used in our Koi guide

Kohaku is one of the koi varieties people search for by name. This page covers what owners actually ask about it, then hands you the sourced koi care guidance that applies to every variety.

Pond fish that outlive their owners — filtration is the whole hobby.

Quick answer: Kohaku is a variety of koi. Everything on this page is koi-level guidance — we do not invent variety-specific numbers.

The care below is koi-level guidance from our species hub, sourced to Merck Veterinary Manual — Exotic & Laboratory Animals: Aquarium Fish and RSPCA — Pond fish advice. It applies to Kohaku exactly as it applies to every other koi variety. We do not publish variety-specific temperament, lifespan or weight numbers that we cannot source.

Pond filtration: the real cost of koi

Koi are heavy waste producers — a single adult rivals several goldfish. The pond needs two zones: a mechanical stage (skimmer, brushes or mats catching debris) and a biological stage (media where bacteria convert ammonia to nitrate), sized generously and run 24/7. Rule of thumb from koi clubs: turn the full pond volume through filtration at least once every 1–2 hours in summer. A bottom drain or strong bottom suction makes cleanup realistic. Test ammonia and nitrite weekly in the first season — that habit prevents most fish deaths.

Feeding: seasonal, not constant

Feed a quality koi pellet in warm months, what they finish in 3–5 minutes, once or twice daily; add treats — watermelon, lettuce, shrimp. Below about 10°C (50°F) water, stop feeding: cold gut bacteria cannot process food and autumn meals become winter deaths. Wheat-germ-based food is gentler in spring and autumn. Never feed bread. In a planted, algae-rich pond, well-fed koi can skip days without harm.