What does a koi pond look like?

As big as possible. Ideally 3ft to 6ft deep rectangular shape is best with no wider than 12 ft as this makes it harder to catch them if needs be. 18 to 23ft is good. Koi ponds can be smaller but this is my preferred measurement. A bottom drain should be fitted or two a skimmer which both will need to be installed when you dig in. It is a good idea to build your koi pond up maybe 3ft for predators and run off from the surrounding area. A filter system to be used which will filter 50 percent of the water volume in one hour. A uv clarifier to keep the water clear and 500 gallons per fully grown koi. Some will go for 250 gallon per loi it is mixed debate.