Koi Ponds, Goldfish & Garden Fish Pond Care

Page Summary: A pond pump is critical for most garden fish ponds. For very large garden koi or other types of fish ponds it may not be necessary to install a pond pump although probably advisable. Why is this? A pond pump is the heart of a normal fish pond. It provides much needed oxygen to the water and more specifically to the biofilter. Inside the pond bio filter are bacterial organismss that purify the water. No oxygen means no purification and thus fish deaths unless pond is large and action of wind is sufficient to add oxygen to pond water.

Submersible pond pumps for koi ponds

Anyone who is serious about keeping koi fish will realise the importance of a good quality pool pump and filter that will keep the water clean, clear and healthy. While koi, like goldfish, will tolerate murky water, they are so beautifully decorative it is silly not to filter the water. If you don't you simply won't see the gorgeous colours and get the full benefit from these gracious creatures.

Both surface and submersible pumps are available for ponds, but the latter type is undoubtedly the more popular type. They are generally smaller and less expensive that surface pumps, yet they do the job competently and efficiently, particularly when used in conjunction with a biological filter.

Submersible pumps have revolutionized koi keeping

When submersible pumps were first introduced to the market, many people were sceptical. After all, water and electricity don't mix, and all pumps need electricity to function. At the time, the usual alternative was a low-voltage pump that was housed on the ground, close to the pond. These had to be carefully plumbed in and protected from moisture. Unless installed below the level of the pond water, they had to be manually primed before they would pump.

The workings of a centrifugal submersible pump

Centrifugal submersible pumps that are suitable for koi and goldfish ponds have three essential parts:

the motor,
the impeller, and
the volute.

The motor, which effectively makes the pump work, has a mechanical section (with the impeller and shaft) and the electrical elements that drive it.

The impeller consists of angled blades or vanes that rotate within the pump. This is where the centrifugal action comes in. The impeller is, therefore a vital part of the pump, directly influencing its performance. Generally high pressure pumps have vanes that are spaced closely together. If the pump has to handle solids, it will normally have vanes that are widely spaced.

The volute, or diffuser, encases the impeller and twists. It directly affects the pressure the pump is able to produce and determines what the discharge pipe diameter should be. So you will use this information to specify pipe work for the pond when you build it.

In addition, most submersible pumps have a strainer on the inlet to prevent fish and debris from being sucked into the pump.

Types of submersible pumps

Not all submersible pond pumps are created equal. Rather there are two basic types, synchronous (that are synchronised with the operating current) and asynchronous. The impeller of synchronous pumps is fixed permanently to a magnet that makes the impeller rotate and pump the water. While there is a magnet in the motor of asynchronous pumps, it is not attached to the impeller. This means that the impeller rotates at a different speed.

How to ascertain the performance of a pond pump

You don't have to be a scientist to work out which is the right pump for your koi pond. But it does help to know what matters, and what makes a pump effective. Two important factors to consider are:

flow rate, and
water head or pressure.

The pump output describes the power of your pump and it is described in litres (or gallons) per hour – which is the number of litres it can pump in an hour. This is its flow rate. You need a pump that will handle the volume of water in your koi or goldfish pond. So the larger the pond, the more powerful your pump is going to have to be. At the same time, take care not to buy a pump that is so powerful it churns up sand and dirt in the pond, because this in itself will make the water murky.

The water head is essentially the height to which a pump is able to spurt water. It is measured from the surface of the water in the pond to the top of the spurting water (the head). As a guideline, fountains use pumps with a water head that will range from about 900 mm to 1,8 m.

When you choose a pump you need to consider every aspect including the volume of the water in the pond, the need for a high water head (if you have a fountain for example, or are incorporating a waterfall), and the required flow rate. Remember that the flow rate and water head affect one another. If, for instance, you are going to pump the water up a rockery, to create the effect of a waterfall into the pond, this will reduce the flow rate.

Another factor that should be taken into account when assessing the potential performance of a pond pump is friction loss. The more pipe work the water has to flow through, the more friction loss there will be, simply because of the resistance it experiences flowing through the pipes. A good dealer will be able to advise.

Tony Roocroft, the owner of this website, has had the privilege of forming close relationships with the UK's leading koi experts... Nigel Caddock and Peter Waddington. Peter J May has also been a firm friend for many years and along with both Peter and Nigel has been a guest of ours in South Africa. Peter and Nigel are world famous koi keeping experts and Peter J May is one of the UK's leading water gardeners and water gardening landscapers. These friends are publishers of world class koi keeping and water gardening books. They have been an important source of learning for me over the years since I first started selling water gardening products in 1992.

Plain, Simple Easy to Understand "Koi" Pond Keeping

In writing these articles I have taken into account all the important questions I have come up against since 1992. Strangely enough most of the queries revolve around a couple of aspects of koi and goldfish pond keeping... paying close attention to these aspects is in fact the "secret" to successful pond keeping. Whether the pond be a koi pond or a goldfish pond the fundamental principles behind the creation of a crystal, clear clean and impressive fish pond are the same.

I will often refer to a koi pond because in my country (South Africa) the vast majority of gardeners want a koi pond when in fact they mean a garden fish pond. The term koi pond in its true sense tends to mean a larger more sophisticated garden fish pond where the only inhabitants are in fact koi fish and large ones at that!

Koi ponds to the true koi enthusiast contain only three things in the words of my friend, Nigel Caddock... "water, oxygen and koi".

Our koi ponds on this site might also contain debris, koi, plants, frogs, goldfish, and other aquatic creatures or fish that take the fancy of pond keepers. Make your pond an extension of yourself... and enjoy the pleasures of water gardening.

On this site we don't pretend to be "Koi Crazy" despite the fact that you will see I refer to koi more often than not.

Make fish pond maintenance easy all year round ... Pond vacs, pond nets tools and protective clothing for cleaning your pond

Fish food and water treatments for pond and fish

Ready for Breeding Koi in Spring

In spring when loves comes around the koi will need somewhere to lay their eggs. In a natural environment eggs will adhere to submerged aquatic plants but in a koi pond there are not always plants because the koi tend to eat them.

You'll be amazed at how simple it can be to breed fish with the help of spawning brushes. You'll need one mature female and at least two males.

Put the brushes one above the other at the edge of the pond. Spawning usually occurs in the early morning after a night of flurried activity and can take several hours. Most of the eggs will stick to the brushes which can then be taken out of the pond and put in filtered water of the same temperature. If the eggs are not separated from the adult fish they may be eaten.