Koi are not just fish – these elegant swimmers are among the most impressive pond inhabitants of all. In Japan, the colourful koi carp symbolise luck, strength and endurance for good reason. Today, they not only enrich ornamental gardens in Asia, but also countless garden ponds throughout Europe.
But if you want to keep a koi fish in a pond in a species-appropriate way, you need to take a close look at its requirements – especially at the right diet. Koi are colourful, but they are also demanding. They need high-quality pond food that is tailored to their needs in order to stay healthy and develop their full blaze of colour.
This PROPOND pond guide is all about koi. You will find out what is important when it comes to species-appropriate nutrition, which pond food is most suitable for koi and how to keep your koi healthy and vital through all the seasons. Frequently asked questions such as ‘How big do koi grow?’, ‘What is the difference between koi and carp?’ or ‘How big should a pond be for koi?’ are also answered in detail here.
General information about koi
Koi fish originally come from the common carp (Cyprinus carpio) and were carefully bred in Japan to become what we know today as ‘Japanese koi’. They are much more than ‘just’ coloured fish – they are symbolic fish with cultural significance.
There are various koi species with many different colour variations. One of the best-known colour varieties of koi is the Kohaku. These koi are white in colour and have red markings. There are several variants of this breed, for example Tancho Kohaku. The red markings consist solely of a red circle on its head, which is intended to imitate the Japanese flag.
Koi carps are sociable animals that need to live in groups. They are active swimmers and explore their habitat curiously. For species-appropriate keeping, they need sufficient space, good water quality and, above all, feeding that takes their natural eating habits into account. This is the only way to keep your koi fish healthy, colourful and vital.
How long do koi live in a garden pond?
The question ‘How old do koi live in the pond?’ concerns many pond owners – and quite rightly so. After all, anyone who puts a koi carp in their pond is taking on responsibility for many years to come. In fact, koi carps can reach an astonishingly high age under optimal conditions. In private garden ponds, life expectancy is usually 20 to 35 years – and with excellent care, even well beyond that.
The life expectancy of a koi fish depends heavily on water quality, their keeping and especially nutrition. But more on this later.
How big do koi grow?
Depending on the breeding line and keeping conditions, adult koi can grow to between 60 and 90 cm long - some even over a metre.
How big does a koi pond need to be?
If you want to keep koi, you need more than just a garden pond – you need a koi pond system that fulfils the special requirements of these impressive fish. This is because koi are not only large-bodied, but also agile and very sensitive when it comes to water quality.
The size of the koi pond is therefore a decisive factor for their well-being and health. Laghetti per koi should be at least 1.2 to 1.5 metres deep so that the animals can survive safely in winter. Pond depths of 2 metres or more are even better, especially for larger groups. As far as volume is concerned, at least 1,000 litres of water are required per adult koi fish - more is always better. So if you want to keep ten koi, you should aim for a pond with at least 10,000 litres of water. The question ‘How many koi in the pond?’ is therefore directly related to the water volume available and the filter technology.
Koi pond accessories – essential for stable conditions
However, pond size alone is not enough. A stable koi pond requires reliable pond technology. The basic equipment includes powerful pond filters, UV clarifiers and air pumps. Products such as JBL PROCRISTAL UV-C Compact Plus 18 W , JBL PROCRISTAL UV-C Compact Plus 36 W oder JBL PondOxi-Set are suitable for this purpose.
Für eine optimale Wasserqualität im Koiteich ist die richtige Dimensionierung des Teichfilters entscheidend. Grundsätzlich sollte das gesamte Teichvolumen mindestens einmal pro Stunde umgewälzt werden – bei stark besetzten Koiteichen oder hoher Fütterung sogar bis zu zweimal pro Stunde. Daraus ergibt sich das empfohlene Filtervolumen: Ein Teich mit 10.000 Litern Wasser benötigt demnach einen Filter, der eine Durchflussleistung von mindestens 10.000 bis 20.000 Litern pro Stunde bewältigen kann. Diese Umwälzungsrate gewährleistet bei entsprechender Dimensionierung der Filterung den Abbau von Schadstoffen, ausreichend Sauerstoffversorgung und somit ein gesundes Umfeld für die Koi.
What is koi’s favourite food?
‘What do koi carps eat?’ is a question posed by anyone who wants their fish not only full, but also healthy and active. This is because koi are curious omnivores with a broad food spectrum – from animal proteins to plant components. In their natural environment - for example in ponds or slow-flowing waters – they rummage through the substrate for insect larvae, small crustaceans, worms, algae or plant remains. They also maintain this behaviour in garden ponds: Constantly on the lookout for food, they like to ‘nibble’ on anything that comes between their barbels.
When it comes to what koi like to eat, protein-rich components are at the top of the menu - especially during the growth phase in spring and summer.
The important thing is: Not everything that kois eat is good for them. It is therefore particularly important to choose the right food composition – and to combine their natural preferences with a balanced diet.
What is the best food for koi?
The search for the best koi food is a key question for many pond owners. Only with the right food can koi stay healthy and display the full splendour of their colour and vitality. High-quality koi food should be orientated towards the natural nutritional requirements of the animals and at the same time be adapted to the conditions in the garden pond. This influences both its composition and its digestibility at different water temperatures.
With JBL PROPOND KOI STAPLE+SILKWORMS , we offer a real highlight in the field of high-quality koi food: an innovative all season koi food with valuable insect protein from silkworms. This special koi food with silkworms not only provides particularly easily digestible proteins, but also contains high-quality fatty acids that strengthen the koi's immune system and intensively enhance their colours.
Why is PROPOND KOI STAPLE+SILKWORMS the perfect koi food?
- Can be used all year round: the formula is suitable for all water temperatures from 10-25 °C – ideal as all-round koi food.
- Species-appropriate composition: with silkworms, salmon meal, plant-based ingredients and a balanced nutrient ratio for natural feeding habits.
- Colour-enhancing & revitalising: supports pigmentation and provides energy for growth and active movement.
- Perfect digestibility: prebiotic koi fish food for healthy digestion and minimal water pollution.
This premium koi food is the perfect choice for koi lovers who value quality, nutrient diversity and a healthy, natural diet.
Species-appropriate feeding with high-quality pond foods specially formulated for koi - such as the PROPOND series – can make a significant contribution to realising the full potential of the animals.
If you want to buy koi food, you should not only pay attention to the price, but above all to the composition of the koi food. After all, the best food for koi is that which fulfils the needs of the animals – not just tastes good to humans.
How often should you feed koi?
The question ‘How often should you feed koi?’ is particularly common among beginners to koi keeping – and quite rightly so. Because koi are not just pond fish, they are active, adaptive animals with a sensitive metabolism. The frequency of feeding depends on several factors – above all the water temperature, the time of year and the size of the animals.
Basically, the warmer the water, the more active the koi are – and the more often they need food. The water temperature therefore plays a central role when planning the feeding intervals. In the warm months with temperatures between 15 and 25 °C, koi can be fed several times a day. When temperatures drop, however, their metabolism slows down – and with it their food requirements.
If you are wondering how often to feed koi, don’t keep to strict feeding times, but react flexibly to the external conditions and the behaviour of the fish. A careful look at their swimming behaviour and activity usually gives you a reliable indication of whether and when to feed.
How much food does a koi need?
Lots of pond owners ask themselves how much food a koi needs. Basically, the food requirements of a koi depend on its size, the season and, above all, the water temperature. The warmer the water, the more active the koi are – and the more food they need.
Koi eat significantly more in summer than in spring or autumn. It is important that the animals are fed regularly, but not excessively. A good guide: the koi should consume all the food offered within a few minutes. This prevents too much food from ending up in the pond and polluting the water.
How long do you feed koi?
‘How long do you feed koi?’ – This question cannot be answered with a fixed date – because the decisive factor is not the calendar, but the water temperature. The feeding period begins as soon as the water temperature rises permanently above 10 °C in spring. It ends again in autumn when the temperatures fall consistently below this value.
During the active months, koi carps can be fed either an all season food that is tailored to their needs, such as the JBL PROPOND KOI STAPLE+SILKWORMS , or a food that is tailored to one of the four seasons.
From protein-rich koi summer food ( JBL PROPOND SUMMER+COLOR ) to easily digestible koi autumn food ( JBL PROPOND AUTUMN+PREPARE ) and sinking koi winter food ( JBL PROPOND WINTER+CARE ), which has been specially developed for the cooler months. The same applies in spring: the right choice of food ( JBL PROPOND SPRING+GROWTH ) optimally supports the metabolism.
Important: As soon as the water temperature drops below 5 °C, koi greatly reduce their metabolism. During this phase, they need to be fed special winter food for koi, if at all. This koi fish food is particularly easy to digest and sinks slowly to the bottom so that the animals can consume it even if they are not very active.
You can find detailed information about seasonal food here: JBL SEASONS
How do you feed koi on holiday?
Probably the most common concern among pond owners is: ‘What happens to my koi when I'm on holiday?’ Especially in the warmer months, when the fish need regular feeding, a longer absence can quickly become a problem. If you don't have neighbours or friends to hand, you should think about a reliable solution early on.
The answer is an automatic feeder for koi. A Koi automatic feeder automatically supplies the fish with the right amount of food at the intervals you select, and is reliable, weatherproof and time-saving. The JBL PROPOND AUTOFOOD model is particularly practical: The automatic feeder for koi ponds not only offers up to 24 programmable feeding times per day, but can also be easily customised to your individual requirements, such as the amount of food or the throwing range.
With an automatic feeder for koi, you can relax and enjoy your holiday while your fish continue to be optimally fed.
How long do koi survive without food?
Another frequently asked question is: ‘How long can koi survive without food?’ Although healthy koi can survive without food for a few days, or even up to two weeks in an emergency, given suitable temperatures and good water quality, this should by no means become the rule. Regular feeding is essential to keep their immune system stable, especially at high temperatures and with active animals.
Which fish can be kept alongside koi?
Many pond owners ask themselves the question: ‘Which fish can be kept together with koi?’. Basically, koi are peaceful animals that get along well with other species - provided these share similar requirements in terms of space, water temperature and water quality.
The following are particularly suitable for socialising with koi:
- Goldfish - robust, sociable and just as easy to care for as koi. Make sure that the koi food is also suitable for goldfish or that you use food specially formulated for both.
- Sturgeon - if the pond is deep enough and well aerated.
- Bitterlings or minnows - small schooling fish that adapt well, but need sufficient retreat options.
Important: Avoid species that are very shy, strongly territorial or sensitive to heat. Perch or fast-aggressive species are also not suitable companion fish for a koi pond. It is also advisable to cater for the needs of different fish species with the help of different species foods. You can find an overview of the PROPOND species food range here: JBL SPECIES
With the right selection you can create a harmonious coexistence and a lively, varied pond.
