Keeping your fish pond healthy

Fish pondNow in my experience, wildlife ponds are easier and cheaper to maintain than fish ponds. However lovely your fish are they do produce excrement daily so polluting the water. They eat your plants and are predators to tadpoles, tiny frogs and other small creatures. But yes, they are beautiful and I completely understand why many of our customers choose to have fish ponds and have a close bond with their fish, wanting to do anything to keep them as healthy and happy possible. For more information on how to build a wildlife pond use this link.

Before putting the fish into your pond

Acclimatize your fish to new water by putting them into a bucket and add a little pond water bit by bit. Do this over as long a period as possible, until the bucket is completely full. You can then transfer your fish into the pond.

Your pond not only must be deep enough to house the fish, but also to ensure the water doesn’t fluctuate too rapidly and stays cooler in summer. Fish are cold blooded and are very sensitive to temperature change. If you want to encourage breeding, the larger the pond, the more space there will be to lay eggs. When building the pond it is a good idea to add rocks for your fish to hide under and if you use tap water to fill the pond, be sure to treat the water to remove any chlorine and chloramines. You can buy kits for this from any good aquatic centre. Once filled, Aquaplancton will get rid of any acidity in the water and ensure the pH level stays around neutral. This is important, because not only can fish become stressed in acid conditions but also blanket weed and algae thrive in acid conditions. Aquaplancton will immediately get rid of any acidity and neutralize the water.

Is it possible to have a fish pond without a pump or filter?

It is possible, but a fish pond needs oxygen for the fish to survive. This can be created with oxygenating plants and regular doses of Aquaplancton. Aquaplancton stimulates the good ‘aerobic’ bacteria which multiply and produce oxygen. In a lot of cases I find our customers tend to buy a pump as well, as the movement prevents the pond from becoming stagnant. As oxygen levels are so vital to the wellbeing of your fish, a bubble stone or waterfall will also help to bring oxygen to your pond.

It is possible to keep a fish pond without a filter, with regular doses of Aquaplancton. The good bacteria that Aquaplancton increases helps to keep the water cleansed of organic wastes and so your pond is healthy for your fish. Unfortunately if you are over stocked, or have nutrition coming in from other sources, the balance can change and you may need a filter as well. Aquaplancton will work well alongside any pump and filtration system. It works particularly well in conjunction with biological filters as it increases the biological action whereas chemicals can destroy it. This all helps to keep your pond cleansed and clear, so avoiding algae growth.

Do you want Goldfish or Koi?

Koi pond

Koi grow a lot bigger than Goldfish so they will need a lot bigger pond than a goldfish pond. A koi pond should be no less than 1000 gallons in volume and at least 4 feet deep, the bigger the better. They will eat more of your plants so limiting the amount of plant life available to be grown. Koi are more expensive and come in a wide variety of colours and patterns. Goldfish ponds need to be at least two feet deep. Goldfish and Kio can live together quite happily in the same pond. When shopping for fish, check that they seem healthy before you purchase and don’t buy too many as they will breed and you can easily become overstocked. If you do buy Koi you may want to make your garden more secure as large and well coloured Koi are valuable.

Over stocking your pond can be fatal for your fish; too many fish may mean they will be poisoned by their own waste. Don’t forget, fish will grow and multiply quickly, so start with one third of maximum quota, you can always add more later if you think your pond will take it. We recommend you have one fish to every square metre (10sq ft), but talking with customers I often find fisheries tell them you can fit more than that in These tend to be the customers who ‘phone us because they are having problems. Better to have a few healthy fish than lots of unhealthy ones. If you do find yourself overstocked, try to give some to a friend or a school or pop some into a nearby village pond.

Do you need to feed your fish?

Well ideally have as many fish in the pond as the natural food production can support. Every time you feed the fish you add phosphorus to your pond which also feeds algae. However, part of the pleasure of having fish is feeding them so you’ll be fine as long as you only give them enough so that they finish in 5 minutes. Feed 1 meal every other day in the winter and twice a day in the summer. If you over feed the fish you will pollute the water and so harm your fish.

Care and maintenance

In hot weather oxygen levels drop, so be very careful if you are planning on turning the pump off. Oxygen levels also plummet during thunderstorms so keep an eye on the weather forecast and make sure your pump is on if there is one due.

Place a small floating ball in your pond in cold weather, if it freezes this will keep part of the water clear, so harmful gasses can disperse. If your pond does freeze over, place a small pan of hot water onto ice to make a hole in order to allow the gasses to escape.

Oxygenating plants are vital. Get your plants established before you introduce the fish and ensure you don’t buy toxic plants. I find Lilies good as they cover the pond surface well, keeping the fish in the shade and helping prevent algae growth by using up nutrients.

Don’t use insecticides or herbicides near the water, even a small amount could poison your fish and will feed algae and, unless you have a raised pond, don’t use lawn fertiliser in the vicinity as it will get washed in when it rains and encourage blanket weed.

Crayfish are a good purchase because they help keep the bottom clean and eat algae, just be sure to give them hidey holes to live under like rocks and plants on the bottom.
If you’re having problems with birds of prey eating your fish you could cover your pond with a net, this also catches any leaves before they drop in, and that’s a real bonus.

Sara Ellis

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