What are koi?
Koi are ornamental carp kept for color, body quality, pattern, and presence. Their deeper story connects East Asian carp culture with the modern Japanese Nishikigoi tradition. A healthy koi hobby starts with stable water, enough space, good filtration, and a trained eye for body and skin quality.
| Foundation | Practical starting point | Why it matters |
|---|---|---|
| Water volume | Plan at least 250 gallons per adult koi; more is easier. | Dilutes waste and reduces temperature and pH swings. |
| Water testing | Ammonia 0, nitrite 0, stable pH, adequate KH, oxygen above 6 mg/L. | Most health problems begin as water or oxygen stress. |
| Filtration | Separate mechanical solids removal from biological filtration. | Clear water alone does not prove ammonia and nitrite are safe. |
| Quarantine | Observe new koi separately for several weeks. | Prevents introducing parasites or serious disease to the pond. |
