Use a properly sized filtration system
Perform regular partial water changes
Test water parameters frequently
Keep ammonia and nitrite at zero
Maintain low and stable nitrate levels
Monitor and stabilize pH
Ensure adequate aeration and oxygenation
Avoid overfeeding koi
Remove uneaten food promptly
Clean filter media on a regular schedule
Do not overstock the pond
Remove debris, leaves, and sludge
Use dechlorinated water for top-offs and changes
Quarantine new fish before adding them
Inspect fish regularly for signs of stress or disease
Maintain proper pond depth and circulation
Prevent runoff from entering the pond
Control algae growth
Keep plants and pond edges trimmed
Service pumps and plumbing routinely