Starting a Medaka Side Business — From Breeding to Sales

Medaka breeding as a side business has recently garnered significant attention as an activity that combines hobby and profit. Starting from a small space, requiring relatively modest initial investment, and with high reproductive capacity, medaka are an ideal beginner's organism for side-business breeding. However, conducting sales on a serious scale requires knowledge of legal procedures, quality management, sales strategies, and more.

The Appeal and Reality of Side-Business Breeding

The reasons medaka breeding is gaining popularity as a side business are clear. The ability to start in a small space, short breeding cycles (approximately 10 days from egg-laying to hatching), and the ability to sell popular varieties at premium prices are the main attractions. Improved medaka can sell for several thousand yen per pair, and rare varieties can fetch tens of thousands of yen per individual.

On the other hand, it's important to understand that achieving stable income takes time. Consistently producing high-quality individuals requires a minimum of 1–2 years of experience, and building sales channels and accumulating trust also takes time. Unrealistic expectations of "easy profit" should be avoided.

Required Equipment and Initial Investment

Here's an overview of equipment necessary for side-business-scale medaka breeding.

Breeding containers: NV boxes and plastic containers are standard. Since you manage different varieties separately, you'll need at least 10–20. A 13-liter NV box typically costs ¥500–800 each.

Containers for breeding stock: Breeding stock that maintains varieties should be managed carefully in slightly larger containers. Prepare 40–60-liter plastic containers for each variety.

Fry rearing containers: Numerous containers are needed to raise hatched fry. Containers from 100-yen shops or buckets can also be used.

Air pump and air stone: Necessary for indoor overcrowding. Using a splitter valve allows one pump to aerate multiple containers.

Feed: Prepare artificial pellets for adult fish, powdered feed for fry, and live feed (Tetrahymena, PSB, Daphnia, etc.).