Goldfish Breeding and Selection Guide | From Spawning to Fry Selection and Rearing | ブリちょく
Goldfish| ✍️ BreederDirect Editorial
Goldfish Breeding and Selection Guide | From Spawning to Fry Selection and Rearing
Explains goldfish breeding cycles, spawning induction, post-hatch fry management, and selection tips. Practical information for both beginners attempting breeding for the first time and breeders aiming for selective breeding.
Key Takeaways
Explains goldfish breeding cycles, spawning induction, post-hatch fry management, and selection tips. Practical information for both beginners attempting breeding for the first time and breeders aiming for selective breeding.
Understanding the Goldfish Breeding Cycle
Goldfish naturally spawn in spring to early summer (when water temperature rises to 15–20°C). While indoor breeding allows multiple cycles per year through temperature management, maintaining a spring breeding cycle aligned with nature is fundamental for raising high-quality fry.
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During breeding season, males chase females in pursuit behavior called "chasing" (tuiboshi). Mature males also develop white pustule-like bumps on their gill covers and pectoral fins—a feature called "breeding tubercles" (tuiboshi)—which can be confused with ich, so careful observation is important.
Females develop a rounded belly before spawning, which can be observed as a visual indicator.
Inducing Spawning and Preparing Spawning Substrate
To encourage natural spawning, establish these conditions:
Gradual temperature lowering and raising: Raising temperature gradually after overwintering (8–12°C) triggers spawning
Water change stimulation: Performing a large water change (30–50%) with fresh water before spawning induces the spawn
Spawning substrate setup: Install aquatic plants (cabomba, water sprite, etc.) or dedicated spawning thread. Provide plenty of materials for eggs to adhere to.
Eggs are adhesive and attach to plants and spawning substrate. After spawning, move the parents to a separate tank (goldfish eat their own eggs and fry).
Egg Management and Hatching
Fertilized eggs are clear to pale yellow; unfertilized eggs appear white and cloudy. White eggs promote fungal growth, so remove them with a dropper or treat with methylene blue solution (commercially available).
Hatching duration depends on water temperature: roughly 4–5 days at 20°C and 2–3 days at 25°C. Newly hatched fry (larvae) retain their yolk sac and don't require feeding for 2–3 days. Once they begin swimming, feed infusoria (microscopic organisms like paramecium), powder food, or baby brine shrimp.
The Importance of Selection (Culling)
Selection is essential for maintaining goldfish breeds. A single spawn produces hundreds to over a thousand fry, but only a portion exhibit the breed's desired traits. Without selection, inferior individuals occupy tank space and hinder the development of quality stock.
Selection Timing:
- 2–3 weeks post-hatch: Remove deformed, abnormally swimming, or non-pigmented individuals
- 1–2 months post-hatch: Perform intensive selection as breed characteristics (body shape, fin form) become visible
- 3–6 months post-hatch: Final selection and confirmation of show-quality specimens
Culled individuals should be responsibly rehomed with trustworthy caretakers or properly disposed of, always adhering to release prohibition regulations.
Fry Rearing Tips
Space and water quality are critical for fry growth. High density slows growth and increases disease susceptibility.
Water changes: Change 30–50% of water daily to every 2 days
Feeding: 5–6 times daily in small amounts (remove uneaten food immediately)
Temperature: Maintaining 25–26°C yields the fastest growth
By selecting premium individuals and raising them with care, you take the first step toward becoming a breeder who brings distinctive goldfish to the world. List your hand-reared goldfish on br-choku and share them with enthusiasts across the country.
