No garden pond is complete without fish. Designing a fish pond is a little more complicated than a simple water garden but not much. Fish eat bugs, especially mosquito larvae. How you design a garden fish pond depends on what kind of fish you want to keep in the pond.
Select the fish. Different fish have different requirements. Goldfish can survive in many areas including those with freezing temperatures. However, the pond can't freeze completely over or the fish will die from lack of oxygen. The pond can't freeze solid from top to bottom either.A pond heater can keep the pond from freezing.
Koi start out the same size as gold fish, but grow to three feet. They require a bigger pond at least three feet deep to thrive. Native fish such as trout, catfish, or minnows have their own requirements as well.
Determine the size of the pond you will need to accommodate the fish you would like. Bigger fish require a bigger and deeper pond. The pond should eventually become its own ecosystem without a lot of help from you. A pond that is too small stresses the fish. The debris and fish waste won't have the space they need to naturally decompose and will rot instead. Too big of a pond requires more maintenance.
Decide on the location of the fish pond. The pond could be hidden behind bushes and flowers to provide a spot to relax or it could be next to the patio for guests to admire. Unless you have a natural spring running through your property locate the pond where you have access to water. Next to a tree might seem like a good idea but tree roots will make digging the pond more difficult. And falling leaves will turn the water acidic as they decompose.
Consider the style of your house. A Victorian style house with a formal garden requires a formal fish pond, perhaps a rectangle, circle or oval outlined with bricks, while a cottage style house would look best with a naturalized pond.
Safety first is an important rule. Wherever you locate the pond make sure that it is safe. A raised pond might be better with children and pets around. If electricity is required for filters or fountains, a licensed electrician should do the installation.