How Many Koi Per Gallon? Stocking Density Guide
By KoiQuanta Editorial Team|
You've probably seen the "inch per gallon" rule. It's fine for goldfish. For koi, it's nearly useless. A 12-inch koi produces waste at a completely different scale than a 12-inch version of most other pond fish, and koi grow. The fish you put in at 6 inches will be 24 inches in four years. A stocking plan that works today can become a disease problem by next summer without a single new fish being added.
Overstocked ponds have 3x higher disease incidence than correctly stocked ponds. That's not because crowded fish automatically get sick. It's because overstocking degrades koi pond water quality tracker, increases stress hormones, and creates ammonia and nitrite loads that the biofilter can't handle. Disease follows.
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