Food: not only the fish but the total environment.
Written by Hugo J. Smal
I don’t know what’s more fun. Buy or feed Koi. I already went into buying the beauties. You can find the story “Buying is more than counting.” So now the focus on feeding. Daily quality time with your fish. The moment to see that they are healthy. Good food makes a huge contribution to their health. In this story, I will explain what “good fish food” actually is.
Feeding on the Goyang Koifarm is very different from what I was used to at home. In my private garden, it was a moment of reflection and pleasure. On the farm, I have to pass about 20 ponds in which hungry beauties shoot at me. From large to small, they are always hungry. Big appetite!
Feeding is already a big drain on the family budget for the Koi hobbyist. For a Koi breeder, food from one of the famous feed manufacturers is almost impossible. This is why we make the food on the Goyang Koifarm ourself.
But first some theory.
What fish not eat immediately starts to spoil in the water. What has been eaten too much comes out undigested and then floats around the fish. If you do not use good food or throw too much of it in the water, the fish quickly swim around in their waste. The pond becomes contaminated and pathogens start to flourish while the resistance of the fish decreases. Large filter installations must convert this waste into (eventually) nitrate and phosphate. At best, this results in excessive algae growth. Feeding should never be overfeeding. The most digestible food is also a must. Moreover, this must have the correct proportions of amino acids.
Koi are large and long-lived fish. I would rather compare them to pets than to downplay them as pond fish. You will love Koi the way you love other pets, they have character and move with you. If you have to give it up, find a good address. People split up because of Koi. Or they come together. Koi gives peace or great frustration when things are not going well. Koi enthusiasts recognize this. Others don’t understand it. Koi has something magical, something big. Koi wants to give you the best food and the Koi food manufacturer wants to make the best food.
But how do you recognize a good Koi food? What requirements should you make of it? There are so many different types of Koi and actually, the variants have different ingredient needs. The latter at least according to the current philosophy.
A Koi is simply a carp, a large and long-lived fish with carp needs and limitations. It is a very smart fish. Carp fishermen can confirm this. The Japanese have coloured the carp just like others have coloured chicken breeds. They have made them more beautiful because they like it, but the basis is and remains a carp. However, it is a fact that Koi are more vulnerable than ordinary carp due to years of breeding programs. This is where water quality and nutrition come into play for Koi.
In nature, carp eat a varied diet of small living organisms that they find in the soil and algae or plant beds. This diet is supplemented with seeds fallen into the water and soft-leaved plants. Thread algae are only swallowed accidentally but hardly digested. A carp’s diet should consist of 80% of animal material supplemented with 20% vegetable.
The carp themselves ensure that they eat what they need. When they are small, especially small water animals. As they grow larger, they add more and more snails, mussels and larger aquatic animals to the menu. As a result, more and more plant material is being added. Old carp are no longer so fast and therefore mainly eat freshwater mussels (high in single-celled algae) and larger crustaceans.
Series of factors determine koi digestion
Just like every living creature, the carp has to eat to grow, mate and swim. Absorbing energy is one of the laws of life. When nothing comes in, nothing can come out. That is why it is important to know how the metabolism works, what a carp needs and what external influences are exerted on this process.
Digestion is the preparation of the food for absorption into the body. We see three steps. 1) Mechanical reduction of the feed. The throat teeth function here as millstones. They grind the food small. 2) The chemical breakdown of the food. The enzymes required for this process in the intestinal tract are produced by the pancreas (pancreas). 3) Absorbing the nutrients.
The undigested food is then discharged into the water. Koi are poor digesters, by the way. After all, they don’t have a stomach. The vast majority of the food is not used. The suspicion is that sturgeons benefit from this. They eat the waste and so get so many nutrients that they can live on it. This is of course not a call to stop feeding the sturgeon. By the way, waste should end up in the filter and not on the pond bottom.
Nutrition and growth
The digestion process is all about growth. The more nutrients the fish can convert, the faster the animal will grow. That is why digestion is not just a matter of ‘what you put in it, you see in growth’. The feeding regime and growth rate depend on many factors such as water temperature and quality, amount of fish in the pond and the genetic background. The need for nutrition is highest when the water temperature rises above 15 degrees. Immature fish grow fastest during the summer months when temperatures are at their highest.
Once the fish has matured, it grows less quickly, because the animal uses the energy to produce sperm or eggs. Fish can continue to grow throughout their life and when you ‘overfeed’ an adult koi, the animal can put the necessary energy into reproduction and growth. When not too many carp swim in a pond, they reach maturity when they are between 25 and 30 cm in size. If the pond is too full, this only happens when they measure between 50 and 60 cm.
Here we come to a problem that every koi lover has to solve. Adult koi grow less quickly. So in a lightly occupied pond, the growth speed decreases earlier than in an overcrowded pond. However, in an overcrowded pond, the feed competition will slow down the growth rate, sometimes even cause stress. Which also has a negative effect.
The pressure on water quality is also considerably greater and often even too great.
Poor water quality affects growth because the koi then eat less or even stop foraging altogether. Poor water quality can also negatively influence the digestion process and thus limit growth. So the hobbyist has to figure out how many fish his pond can have.
The amount of water and filter capacity are the most important parameters. The genetic background plays the same role in the growth process as in humans. Digestion and the season’s Spring: energy is used for the production of eggs, sperm and hormonal development. Summer: energy is used for skeletal, muscular and skin development. Autumn: energy is stored for the coming winter. Winter: energy is used to survive. This seasonal energy distribution does not apply in a heated pond. If you keep the pond at summer temperature 365 days a year, adverse consequences can occur. Distorted koi, loss or breakage of colours, tumours on the reproductive organs and accelerated ageing are attributed to this way of temperature management.
Water temperature and nutrition
The temperature of the water has the greatest effect on the growth of fish. They are cold-blooded. Their body temperature rises and falls with the ambient temperature. When the water temperature drops, the ability to digest and absorb nutrients in the body also decreases. That is why it is advisable to give only easily digestible food below 10 degrees. This is digested quickly and easily.
A heavy digestible diet stays in the intestines for too long, which can cause all kinds of problems. Bacteria, which normally play a role in the digestive process, can then even become pathogenic (pathogenic) bacteria. When the water temperature rises again, the fish needs protein to grow, to recover from winter and to reproduce.
A piece of often-heard advice is: give as much food as the fish can eat within 5 minutes. Still, it might be useful to specify this a bit. Small koi (under 15 to 20 cm) need 5% of their body weight per day, while larger koi can already manage 2%. It is recommended to feed young koi more often than adult koi. Because they have a shorter gut, the digestion under the same water conditions performs less than that of the larger fish, while it needs to process more food.
Summary of Digestion
Growth, the genetic background of the koi, feeding regime, water quality and water temperature, amount of fish in the pond, everything has to do with everything. The art of keeping koi is therefore to coordinate all these things. Failure to do so will cause problems. Therefore, invest in good food, so that the water is not overloaded.
A food with a high digestible protein is always recommended. Unfortunately, one protein is different. Inexpensive feeds even use indigestible proteins. This is only to be able to write a higher protein percentage on the packaging label. You can almost say that these percentages mean nothing because you don’t know whether they are digestible proteins.
Correct proportions of amino acids and essential amino acids are very important. A little too little of one specific essential amino acid means that some of the other amino acids (even if they are from easily digestible protein sources) cannot be used to build protein (muscle mass, length). So protein is not used and you can expect, among other things, fatty tissue or a lot of water pollution.
So it goes even further as just digestibility
Whether your fish can use the ingredients is perhaps of much greater importance. The vitality of Koi is also related to good water quality and good food. So it’s not just about the fats and proteins!
Proteins in the food mainly come from the fish meal used. Fish meal comes in many types and qualities. The lowest quality is, of course, the cheapest and is therefore used in the cheaper feeds. This fish meal is made from fish waste. This is ground, boiled and dried. By cooking, at most half of the proteins are difficult to digest by the Koi. The other half provides lush algae growth in the pond.
The highest quality is LT (low temperature) fish meal which is processed at much lower temperatures and consists of pure fish. Automatically the percentage of fish oil in this is also much higher. These proteins are 90% digestible by the fish. The LT fish meal can be made even more digestible by pre-digesting the LT fish meal with enzymes. Almost 100% can then be absorbed. A side note is of course that the Koi must have genetic properties (good variety + bloodline) for rapid growth.
What do you expect from your koi?
You want Young “Junior” Koi to have a good start. They must grow into beautiful adults. Of course, you prefer to see them grow into jumbo koi. For this, they need easily digestible proteins. Vitamins and minerals should not be missing to develop a good body and bone structure.
Adult Koi grow at a slower rate but put more energy into their body shape and develop their colour. That is why it is essential to adjust their diet accordingly. You must and want to ensure that they get a feed with the right ingredients to do this. You want all the potential in terms of colour and body shape in the Koi to come out.
At all stages of Koi’s life, water quality is just as important to their health and development as the food they consume. After all, they have to grow into jumbo Koi
There is also special food for those submarines. Your jumbos must maintain their body shape. You want her to get even better. The same applies to the colour splendour of your fish that you appreciate so much.
When you give large amounts of proteins, they do not grow faster.
To be honest, the exact opposite is true! Lower amounts of digestible highest quality proteins provide good support for their health and colouring. They ensure that your Jumbo Koi will reach their maximum genetic length. After all, you want your darlings to grow old very healthy.
I am sure this info will help you choose the right food. I press the button of the feed mixer again. First I mix the pellets dry with ‘Fish pro’, stabilised Vitamin C and Aqua impact. These are products of www.handongvet.co.kr. As a basis, I use feed from CheilJedang. I hope to give you more information about this soon. When properly mixed I pour some water to let the ingredients stick to the pellets. Plant oil is believed to be better. Then I hit the button again. Afterwards, the pellets must be dried for a day. I’m sure the Koi love the effort.
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