In spring, compare each koi's activity and condition with the recovering pond system. Increasing interest in food is encouraging, but it is not evidence that a wintered filter can process a full summer ration. Check the fish and water before making that increase.
Observe without Disturbance
Watch the group before food is offered. Note breathing, balance, skin, fins, and any newly isolated fish. Gradual activity changes can follow warming, but sores, persistent rubbing, gasping, or loss of balance need investigation. Do not explain every sign as spring adjustment.
Check Water and Equipment
- Representative temperature and recent daily trend.
- Ammonia and nitrite, with pH and alkalinity for context.
- Actual aeration and filter flow.
- Water level, overflow, winter damage, and recent source-water additions.
Restart Feeding Conservatively
Follow a complete food's temperature guidance and the actual fish response. Start small under suitable conditions and monitor the filter's response before increasing. A universal minimum protein percentage is not a spring prescription. Read feeding through the seasons and digestion and temperature.
Avoid Automatic Treatments
The season alone is not a diagnosis of parasites or bacteria. Do not add salt, preventive medicines, or a mixture of water-balancing products on a calendar. If signs appear, document them and obtain appropriate examination or testing. New purchases still need separate quarantine.
Keep the System Work Separate
Perform needed debris and equipment maintenance without repeatedly chasing fish or destroying established filter media. The detailed spring start-up guide covers the equipment sequence; this page focuses on the koi's condition. Severe deterioration needs urgent support alongside the first checks.