Sick koi? Match the symptom → take the right next step.
This site is built to help pond keepers quickly sort what’s urgent, what’s common, and what to check first—without guessing or throwing random treatments in the pond.
Flashing / rubbing
Often irritation—parasites, water swings, or microbubble/gas issues.
Go to flashing triage →Ulcers / red sores
Usually bacterial involvement + underlying stressor (often water quality).
Go to ulcer triage →Lethargic / not eating
Temperature, parasites, gill issues, ammonia/nitrite, or chronic stress.
Go to lethargy triage →Gasping at surface
Not always “low oxygen”—can be CO₂, gill damage, irritation, or water issues.
Go to gasping triage →Before you treat anything
If you only do one thing right now, do this:
- Test: ammonia, nitrite, pH, KH (alkalinity), temperature.
- If ammonia/nitrite are present: prioritize water change + detox + aeration.
- Avoid “shotgunning” meds unless you have a plan and can follow directions precisely.
Want product-level help?
If you want recommended product options for common koi health and water-quality problems, visit Aqua Meds.
Disclosure: SickKoi.com may reference products sold by Aqua Meds. Links are provided as a convenience.