Fish Care FAQ

How do I take care of my fish during the winter?

Your fish do require access to fresh air during long periods of frozen ice in the winter. You may let your waterfall continue to run as it has all season, (but there are better options). The moving water will not freeze and will provide the needed air exchange. Even in severe cold, ice will form over the moving water, but the flow will not stop. There are a couple of concerns with this option: First, a temporary power outage might allow water to freeze in the line blocking the water flow even when power resumes. Second: in a severe winter ice dams can form on a waterfall or stream causing water to back up and start a leak that would never occur in the summer. For these reasons, if you expect to be away from your pond for extended periods over the winter, we would suggest one of the following alternative methods. One option is to disconnect the pump from the waterfall (or use a separate pump 175 gph or larger) and place it on a shelf about 6-8” below the water surface with the outlet pointing up so that it creates a bubbling, mini-geyser at the water surface. When plugged in, this moving water helps prevent total freezing of the surface.

How many fish should I put in my pond and what kind?

A pond will support only so many fish. For example, if you have a 1,000 gallon pond then we would recommend adding 10-12 goldfish, 3” to 6” long to your pond. With good filtration, a good formula to use is: one goldfish for every 50 to 100 gallons or one koi for every 200 to 250 gallons. This allows the fish to reach mature size in a healthy eco-system.
We recommend using any type of hardy goldfish (Shubunkins, Comets, Fantails) as they are cold water fish and can live in your pond all year. Koi are also hardy and are available in many stunning colors plus they have a long life span (30+ years). A less common fish is the Golden Orfe and although not colorful, they swim rapidly and in schools so they are great fun to watch.

Can fish live through the winter?

Absolutely! As long as you have a depth of at least 18” there are a variety of fish you can enjoy in your water garden all year long. An air hole must be maintained if there is ice covering the pond so floating de-icers and/or aerators are very helpful in achieving this.

How can I keep predators from eating my fish?

Pond netting, fencing, predator decoys, and motion sensor activated deterrents are all effective.

I've heard that koi will eat your plants. Is there any way that I can combine a water garden with a koi pond?

Although some koi-keepers experience problems with their koi eating or uprooting their plants, the majority of our koi keeping customers also have plants in their ponds. Use large cobbles on top of your pots (surrounding growth point) to keep koi from rooting. Plant protectors are also available to protect the roots of floating plants or to keep fish away from submerged plants and pots. Koi may find some types of plants too appealing to ignore. However, with plant protectors to keep the fish from rooting them up, you should be able to keep any plant that you wish to grow. Many people will also create a 2-tiered pond. Keep the koi in the lower pool and then the upper pool can be used for plants with no limitations or risk to the plants.

What happens to the fish in the winter?

Goldfish and koi are the two most frequently kept pond fish and they are able to tolerate temperatures in the low 30's. Their metabolism slows down in the winter and they should not be fed. They mainly hang around at the bottom of the pond where the water temperature is about the mid to upper 30’s ( in degrees Fahrenheit) even when the surface is frozen. This is because the surrounding soil insulates the lowest water levels well, assuming the pond is in-ground . An area of the pond must be kept ice-free to allow for gas exchange. A detrimental situation would be if a pond was entirely covered with ice for approximately 2 weeks because the build-up of toxic gases would kill the fish.

Do goldfish and koi reproduce?

Yes, both goldfish and koi lay eggs to reproduce. Spawning typically takes place in spring when hundreds of eggs are laid. Many of the eggs are never fertilized, then many more are eaten by the adult fish. Those that hatch are still at risk for several weeks from being eaten by the adults. Still, many can survive in the pond to adulthood. Fish spawns are one way it is easy to end up with an overpopulated pond.

How large will my koi be once they are full grown, and how large should my pond be to accommodate them?

In five years a koi can grow to be 18 - 24+ inches long. Because of this, you need to make sure they have enough room to grow and live. Koi ponds should have at least 1,000 gallons of water, and it needs to be at least 2 ½ - 3 feet deep. If you live in an area that experiences especially harsh winters, you may want to check with a local pond supplier to see if your pond needs to be even deeper.

What do I need to do to keep my koi healthy?

This answer has multiple parts. First of all, you need to keep in mind that the health of your koi is directly related to both water quality and proper nutrition. With that in mind, the following points should help keep your koi healthy:

  1. Keep the pH of your pond water between 6.8 and 8.0. Monitor the ammonia and nitrite levels to make sure they always remain at zero. If these numbers go above zero at any time, that means you are overfeeding your koi or there are too many of them in your pond. 
  2. Remove 25% of your pond water and replace it with de-chlorinated tap water once a month. 
  3. Feed your koi only fresh, nutritionally balanced food. A complete selection of our fish food can be found here. Don’t overfeed your koi, because that can lead to an increase in ammonia, nitrite and nitrate levels. 
  4. Don’t add too many koi to your pond. Overcrowding is the main cause of disease outbreaks and fish loss. You should have roughly one koi for every 200-250 gallons of water in your pond.
  5. Buy koi from reputable dealers that quarantine their fish before selling them.

Do I need a pond filter in my koi pond?

Yes, all koi ponds need a filter. Fish waste, along with decaying plant matter, can create a build-up of toxic materials in your pond. A pond filter will help remove these toxins and ensure that your fish have a healthy environment in which to live. There are many different varieties of pond filters available, research your options to find the best model for your pond or call us for assistance if you have questions.

How do I know what food to feed my koi?

The diet for your koi should be dictated by the temperature of the seasons. In cooler temperatures, when your pond water is between 42 degrees Fahrenheit and 65 degrees Fahrenheit, your koi need a high carbohydrate/low protein diet. Your koi’s metabolism slows down when the temperature is cooler, so they need less food with very little protein in it. Blue Ridge Cool Water Wheat Fish Food is a good choice. Once water temperatures falls below 42 degrees Fahrenheit, you should stop feeding your koi altogether. When water temperatures are warmer, above 65 degrees Fahrenheit, your koi need food that has greater amounts of protein, fats, minerals and vitamins in it. Blue Ridge Main Season Blend Fish Food or Sho Koi are good options.

Can I have both koi and goldfish in the same pond?

Yes, you can. Keep in mind that adequate filtration is critical with koi because they grow much larger and can live much longer than goldfish.