How Many Koi Will My Pond Hold?

This is a loaded question, because if you put as many Koi in a pond as it will “hold”, you may no longer like your pond. If you visit Keystone Hatcheries during koi season, you will see Koi holding tanks that are about 1,000 gallons and have hundreds of Koi in them. Does that mean you can put hundreds of Koi in your 1,000-gallon pond? Probably not.

The default rule of thumb for the amount of Koi in a water garden is ½” of fish for every square foot of water surface area. Keep in mind, this is the amount of Koi suggested to peacefully coexist with your pond. the pond can almost certainly hold more, but your water quality may deteriorate, and your fish may tear apart your plants! Also, the fish will become increasingly dependent on you for food as the density increases. Low-density fish ponds require far less feeding than high density. For instance, the fish in the author’s home pond have never been fed…they simply live off of the natural food that grows within the pond,which is doable because of the relatively low density of fish.

Dedicated Koi ponds generally have higher densities of fish, and as a result they have greater waterflows, better filtration systems, and supplemental aeration. Still, the number of Koi that any given pond can hold depends on many factors, including the water quality you want, and how much/often you want to feed the fish..