1. Sufficient Water Volume and Advanced Filtration System

• Pond Capacity: The total water volume must be at least 30 tons, ideally 80 tons or more, to provide ample space for growth and a stable ecological environment.
• Filtration Setup: A high-efficiency multi-stage filtration system (mechanical, biological, and chemical) is essential, supported by a powerful water pump circulation capacity (circulating the total water volume 1.5–2 times per hour) to maintain long-term water quality that is "living, clear, and fresh."

2. Careful Selection of Koi with Genetic Potential for Large Size

• Parent Fish Selection: Prioritize female koi from reputable bloodlines (such as Dainichi, Sakai, or Momotaro), as genetic potential is the foundation for achieving large size. Avoid selecting individuals of unknown lineage based solely on low cost.
• Stocking Density: Maintain low stocking density—no more than one target koi per ton of water—to prevent competitive stress from hindering growth potential.

3. Scientific Rearing Techniques and Precise Management

• Water Quality Control: Maintain stable conditions year-round: water temperature 20–28°C (heating required in winter), pH 7.0–7.5, ammonia and nitrite levels near zero, and dissolved oxygen no less than 6 mg/L.
• Nutrition Strategy: Implement a phased feeding approach: high-protein feed (≥40% protein) in summer, balanced feed in spring and autumn, and easily digestible feed in winter, supplemented with vitamins and minerals.
• Disease Prevention: Establish regular quarantine measures and preventive medicated baths, with particular attention to early intervention for parasitic and bacterial infections.

4. Long-Term Commitment and Resource Investment

• Time Investment: Growing giant koi typically takes 8–15 years, requiring daily monitoring of water quality, feeding adjustments, and health observations.
• Expertise Development: Deepen knowledge in koi physiology, water chemistry, and pathology, or entrust the koi to a professional koi breeding facility for managed rearing.
• Cost Awareness: Annual expenses for electricity, water, premium feed, treatments, and equipment maintenance can amount to tens of thousands of yuan, requiring adequate financial preparation.

5. Environmental Stability and Risk Management

• Disaster Preparedness: Design the pond to account for extreme weather events (heavy rain, high temperatures, cold snaps) with measures such as shading nets, insulation covers, and backup generators.
• Emergency Plans: Establish rapid response protocols for sudden power outages, drastic water quality changes, or disease outbreaks to prevent years of effort from being undone by a single incident.

Key Reminders:

• Raising koi over 80 cm is a "systematic project"—any weak link in the process can lead to failure.
• True "refined rearing" is the integration of resources, technology, and patience. Achieving such size with low cost is nearly impossible. While pursuing growth in length, it is also essential to balance the koi's skin quality, body shape, and swimming posture—this is the true essence of koi keeping.