Make your pond deep
Depth of your pond is very important. You pond should be at least 4 feet deep, however it is best to provide for your fish six or even 8 feet deep pond. This will ensure that your fish are protected from raccoons, cats and other animals who can empty your pond. Deeper fish pond also helps to maintain water temperature in the middle of summer
Koi really love a lot of room to swim
Small ponds are no good for koi. Remember, with time they can grow quite large and they will need a big space. Also there are so many color variations of koi, that as time goes you will probably want to add more fish to your pond. So it is better to create a large garden pond from the start than rebuild it later. About ten thousand gallons is a good size for a garden fish pond, bigger would be even better.
Provide some heating in colder months
Unlike tropical fish, koi don’t suffer much from cold; however you should never let your pond freeze completely. Installing a proper heater for backyard ponds will always keep an opening in the ice. Also keep in mind, that like most fish koi only grow when the water is warm, so with a heater your fish will grow faster
Plan some shade for your koi
When selecting where to place your pond, make sure it is out of direct sunlight. Also keeping water plants like water lilies in your pond makes sence – not only they add beauty to the overall look of your pond, but they also provide shade for the fish. However, you should avoid building your pond under trees. Cleaning a garden pond of fallen leaves is a nightmare.
Plan to install a bird net
There are many birds of prey that will enjoy eating your koi. Don’t give them the opportunity; plan your pond location so it is possible to protect it with a net.
Keep insecticides away from your pond
When planning your pond keep in mind that you should not use any insecticides or herbicides near the water. Even a small amount of common garden poison can destroy your beautiful fish.
Pumps, filtration systems and other fish pond accessories
Several accessories are nessesary for healthy garden fish pond. Ideally you should get a water pump, filtration system, pond water aerator and an ultraviolet sterilizer. If the water in your pond is still, your pets might feel unwell. Koi pond filtration systems are pricey, so as an alternative you can make your own homemade filters.