Water Garden or koi Pond ,you must make that decision before you build your garden pond after wards it will be too late to change your mind. In any kind  of garden pond filtration is the most  important aspect, usually this is accomplished by setting up an ecosystem where fish, plants, and beneficial bacteria live in mutual accord. Pumps are added  as much for decorative waterfall displays  as as for water circulation and aeration. Mechanical filters are initially added to support the biological filtration and reduce the amount of pond  maintenance necessary for the home owner . But as more fish are added or existing fish increase in  size, the filter plays a more increasingly vital role in the overall health of a garden pond.    Such items as UV lights and bottom drains are under water lighting  are optional extras.

In a Water garden water depth is usually approx 24” or less. For most places this depth of garden pond is adequate  for over wintering  fish, where winter temperatures do not drop substantially below zero. But check for your specific area ,as to  what the frost line is supposed to be .Frost line may be  defined as the depth to which frost penetrates the earth.   Or to a garden pond builder the depth to which pond water will freeze. Here in Niagara, Canada the frost line was we were told 30in so we dug our first garden pond to the depth of 3ft 6in allowing more 6in of unfrozen water in which our pond fish could survive the winter.  I guess for most years that is correct but on a couple of occasions over the 15 or so years we have been ponding in Niagara the winter weather has gotten  substantially colder and the garden pond froze almost completely and we  lost all but the smallest fish.
Koi ponds on the other hand require a minimum depth of 4ft irrespective of location

A water garden is safer for kids than a deep koi or garden pond although please be aware that it is possible for a small child to drown in just a couple of inches of water and personally I WOULD NOT RECOMMEND THE INCLUSION OF ANY KIND OF GARDEN POND IN GARDENS WHERE SMALL CHILDREN PLAY UNSUPERVISED there are some beautiful alternatives to garden ponds that I will discuss in a later posts.

GARDEN POND PLANTS

It is much easier to tend to pond plants growing in the shallower  depths of a water garden than it is those that may be incorporated into a much deeper a  koi or garden pond. Most water  plants do not need great depths of  water in which too thrive, most only really need a few inches ,and will in fact suffer if covered by too much water. Despite the fact this may be overcome by planting them on some form of raised pedestal or floating island  that can be placed in deeper water, they are often very hard to maintain in these kind of situations.

In a water garden the  plants are the main focus of the water feature and aquatic plants whether floaters ,marginals or rooted in pots residing on the bottom of the pond generally far out number the fish by a long way.
In a true koi pond plants are not generally included the koi are the main attraction , koi will actually eat the plants or deliberately uproot them just for entertainment, so if you decide on combining a koi pond and water garden into one garden pond, which of course is a definite option ,the koi proclivity for plant destruction must be born in mind and steps taken to protect your valuable aquatic plants from the destructive habits of the koi.
The inclusion of water plants in a water garden or any small garden pond can serve double duty, not only as a beautifying factor but often for the smaller water garden or pond, the plants alone can act as a filter for the  water, sometimes even as the water gardens or garden pond ’s only means of filtration.

This would never be possible in a koi pond, or a bigger garden pond ,bigger ponds are just too large containing just too much water, and the koi themselves produce too much waste, for the water to be kept clean by solely biological filtration supplied by just pond plants .

Water circulation/pump size are other factors to consider “Sometimes” a small garden pond or  water garden can be maintained and aerated with a smaller sized  water pump, particularly when only a water fountain or 2” wide trickling waterfall is desired. The Larger the garden pond, the bigger the pump necessary  as the  volume of water it must handle is much greater than in a a small water garden.  However the greater the  pump flow, makes for much more impressive  waterfall displays but is also  a cost factor that should be born  in mind.

Koi are a unique fish possessing a beauty unequaled by any other garden pond fish, their growing popularity due mainly to their extreme good looks and wide variety of colors and patterns. Koi often have engaging personalities each possessing just like humans certain character traits and quirks .A Koi can become a beloved family pet,coming to the surface of the garden pond and begging for food whenever someone comes near and may even be coaxed to eat out of your hand. So it’s not surprising then that when referring to a “Koi pond” it is a pond rather different in construction than a mere garden pond, generally the term koi pond refers to ponds designed for just Koi. Plants playing a secondary role and may not even be featured at all.

Most koi pond owners consider that plants interfere with their view of the Koi and don’t include them,  bigger  Koi often  damage plants  due to their sheer size and sometimes just for something to do. Koi often grow to be more than 30-inches long and can live for thirty or forty years if treated correctly. The usual life span of koi in Japan is seventy to eighty years. Some have been known to live to be hundred or even more years in age, such as the fabled Hanako, claimed to have lived for over 226 years. Unlike these astounding results produced by the fastidious care the Japanese give their koi, North American koi live a fraction of that time, usually due to neglect and lack of care or improper housing.

The enchanting story of Hanako a koi fish who ostensibly lived to be 226 years old. During the last portion of Hanako’s life, her keeper was a Dr. Komei Koshihara, president of Nagoya Women’s College in Japan. Koi Adventures has a translated copy of a 1966 speech given by Dr Koshihara about the ancient fish Hanako, who in 1977 finally went to play with the angels in that bigger koi pond amongst the clouds. From Koi Adventures:

“Hanako” is still in perfect condition and swimming about majestically in a quiet ravine descending Mt. Ontake in a short distance. She weighs 7.5 kilograms and is 70 centimeters in length. She and I are dearest friends. When I call her saying “Hanako! Hanako!” from the brink of the pond, she unhesitatingly comes swimming to my feet. If I lightly pat her on the head, she looks quite delighted. Sometimes I go so far as to take her out of the water and embrace her. At one time a person watching asked me whether I was performing a trick with the carp. Although a fish, she seems to feel that she is dearly loved, and it appears that there is some communication of feeling between us. At present my greatest pleasure is to go to my native place two or three times a month and keep company with “Hanako”.

A KOI POND

Koi can live and thrive in any  garden pond environment so long as it is built with the koi as first priority rather than plants so long as the water garden design incorporates some or all of the features required for Koi keeping. The most important factor when keeping koi is water quality the number one  thing you must constantly remember to do is keep testing ithe water,  you need to test the the pond water for its level of  pH, hardiness, ammonia, nitrates, and nitrite levels.  This testing is important to keeping your fish alive this is not anywhere near as complicated or as scientific as it sounds test kits are available usually costing less than $30 that will test the water for all of these chemicals if you have ever had a swimming pool you will be used to testing water quality with test kits in the case of a garden pond you simply have to take readings on a wider range of chemicals.

There is no one plan or design that every garden pond owner must follow, for a Koi pond, or water garden or a combination of the two where Koi and plants intermingle. A garden pond design is first dependent on budget,then on  environment or climate, location and ground conditions. It is paramount that the primary purpose of the garden pond must  be decided on before any construction takes place. Is the ponds first function to house pond fish either koi or goldfish or is the garden pond to be mainly an aesthetic focal point for your yard or garden and only you can decide that and it must be decided first not last.