Breeding

Koi breeding is where science meets art. A single spawning can produce tens of thousands of fry, but fewer than 5% will develop patterns and body conformation worth keeping. Understanding genetics, managing spawning conditions, raising fry through critical developmental stages, and making informed culling decisions are skills that take years to develop.

Most hobbyist ponds will experience unplanned spawning at some point — koi are prolific breeders once sexually mature (typically 3–4 years). Whether you're intentionally breeding for quality or managing unexpected fry, these guides cover the biology and practical techniques involved in koi reproduction and grow-out.

Guides in This Section

Genetics Basics

How koi color and pattern traits are inherited, dominant vs recessive genes, and why parent quality doesn't guarantee offspring quality.

Spawning Conditions

Temperature triggers, spawning media, male-to-female ratios, controlled vs natural spawning, and egg collection.

Fry Care

First feeding, live food cultures, water quality in fry tanks, growth stages, and mortality management in the critical first weeks.

Culling & Selection

When and how to cull, what to look for at each growth stage, pattern development timelines, and ethical culling practices.

Grow-Out Systems

Mud ponds, above-ground tanks, indoor systems — facility options for raising fry to saleable size.

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