May 6

All You Need To Know About Koi


Koi FishKoi fish are a delight to pet and nurture. They are very vibrant in nature; with them around it’s never a down-moment. If you are looking to get new fish for your aquarium, please do read this. This article serves to show you all the wonderful attributes of this fish, basically, all you need to know about them. At the end of this article, you should be able to adapt and take care of your own Koi fish.

Average size

Koi fish have a length ranging from 22 inches to 26 inches. This is an average: which means that some can even have the range of 34 inches to 36 inches in length. The smaller guys will have a length of around 12 inches to 15 inches. Owing to its massive adult size and similarities with goldfish, some even call the Koi a giant goldfish.

Koi may grow at a rate of one inch per day given that you maintain good living conditions. For a higher growth rate, try foods that are rich in proteins. An overdose of carbohydrates makes the Koi belly grow fat and stunts its growth. You should also avoid overcrowding the aquarium if you want them to grow faster. An overcrowded environment will stress the fish and reduce the growth rate. For this to happen, it would have been a result of competition for space, food and other resources.


Koi fish serve as ideal pets. They have a very long lifespan, the average of which is around twenty-five years. This means that some even live longer than this – imagine that! Some have been recorded to have lived for up to thirty-five years, which is quite impressive. One’s grandkids might even live to see one’s Koi. Some also say that a lifespan of about a hundred years is also possible for them – given the right conditions to grow in.

In order to ensure a longer lifespan for your Koi, you need to carry out maintenance in a gingerly manner. This means the right temperature and pH have to be maintained. The water to fish ratio should be according to the acceptable standard. This means around 29 gallons for small fish and around 50 gallons for adult fish.

Hey! Avoid dangerous chemicals. These may be picked up from dangerous water sources such as open water bodies that have been exposed to industrial waste. Chlorine concentration, if too high, can cut the lifespan of your fish. This means that you should watch your water source and maintain fresh, clean water.


Well, it’s quite easy to pick out Koi fish from other species. They are a colourful lot. In most case, they are white with an array of bright colours on their surface. In other cases, they come in plain bright colours. Orange is a pretty common colour. Some may even have red or black spots. These spots are usually in the form of irregular shapes which come in many different sizes.

The Koi is a beautiful breed of fish. They are colourful and very attractive to gaze at. Here are some of the common colours associated with the Koi fish: red; yellow; blue; white; orange; black. These colours may actually be the basic plain colours or the colour of the other spots. You can play around with the colours if you are well-versed with the breeding of Koi. If you do not know-how, you can get assistance from the Pros. Breeding is fun, you can learn and master it.


The Koi are a very peaceful kind. They can relate well with other types of fish. They are, however, very energetic yet not aggressive. In addition to their high energy, Koi fish are a hyperactive eater. They eat almost anything. They do enjoy the company though. They can live in twos, threes or even way larger groups if the resources are sufficient – being tank space and sufficient food.

Koi fish are pretty smart. I mean, you can teach them tricks, and even feed them off-hand. They are very playful if you ask me. They do however get nasty when it’s time to reproduce. They can eat their young ones. So, you might have to separate them from the Koi fries when they are mating or any time near the mating season. You can do this by putting them in a separate tank.

Aquarium Conditions

For Koi fish – you need to maintain steady temperatures ranging from 18⁰C to 24⁰C. This translates to 65 – 75 Fahrenheit. The required pH ranges from 7 – 8,6. This data means that Koi needs neutral to slightly basic conditions. This fish does not prosper well in acidic conditions. You can test the pH with DIY pH kits when you change the water in your tank.

Koi fish like warm temperatures. If you put them under cold conditions, chances are that their activity will greatly reduce. As for high temperatures; these seem to have no effect on Koi.

As much as they can withstand a broad range of temperatures, they do not like rapid freeze-thaw action. Avoid the habit of changing the temperatures suddenly. This means that before tanking your Koi, place their water bag in the tank for some minutes until slow adaptation takes place. After that, you can then proceed to let the out of the bag into the aquarium.


The Koi’s diet is not that demanding to keep up. This pet is an omnivore – which means they can take both organic and meat-based foods. They can eat many horticultural products.

Examples of these are peas, lettuce, some forms of beans, algae and rice – almost the whole human diet is edible to them. They are not picky at all, all you have to do is maintain a good nutritional balance. This means that if today you gave them some insects, for example, tomorrow try rice or shrimp. If you want to give them the best though, try specialised pellets, made specifically for your Koi fish. This is especially handy in dishing out proteins.

You may feed Koi fish up to once a day. The food should be eatable in around 4 minutes. Overfeeding is not a good idea though. If you notice that your fish can’t finish the food in the stated time, you should readjust the amount you are giving to the fish. A very interesting fact about Koi fish is that these guys can actually go up to ten days without food – and this will not be of any detriment to their health. This, therefore, allows you to take it easy on the food quantities. Even though the previous statements are true, they like eating and can eat almost anything.

    Aquarium Mates and Compatibility

    Koi are not picky when it comes to company. They can share the aquarium with various kinds of fish. This is due to their docile nature and low aggression levels. They may however be irritating to calmer breeds. This is because Koi fish are very energetic.

    Make sure, though, that you do not mix Koi fish with more aggressive breeds. They will probably suffer the consequences of the mismatch because of their calm nature. So if you find a happy species that enjoy peace and calm – you can add it to your Koi aquarium. Aquarium mates should favour almost similar conditions and attention as the Koi. There should be no competition for resources or care.

    Some good examples of aquarium mates are barbs, barbells, catfish, goldfish, pleco, tench, golden orfe, and sturgeon. Fish like Gourami won’t do because they require different temperatures – they are tropical fish. Additionally, the difference in their sizes on reaching maturity will result in hostility. The best aquarium mates are bottom feeders, this means that there would be less conflict amongst them.

    Common Myths

    There are many different myths surrounding the Koi fish. Most of these myths are of Japanese origin. This is why people – over the years – have developed low-key respect for Koi fish. Koi fish are believed to be good fortune. In the end, some people keep them to maintain their prosperity. They are the Japanese Samurai symbol.

    As displayed in an ancient Japanese legend; they signify perseverance and determination in reaching one’s goal in the face of adversity. Their unique colours are also rich in meaning. Black is for patriarchy. Red stands for might and vigour. Blue on the other hand stands for peace and tranquillity. Orange is for character and determination. So this is why some colours are more expensive than others.


    One should be comfortable with cleaning the aquarium consistently for Koi to live longer. When you clean your tank, avoid traditional detergents like soap; these may be harmful to your fish. Also – you might want to avoid touching Koi with your bare hands. First, this will remove the layer of fluid used by the fish for adaptation. That fluid substance may also be harmful to human health – especially that of kids. If your child however handles the fish, wash their hands thoroughly to remove the substance completely. Keep both yourself and your fish safe.

    One can also keep checking for droppings to avoid conditions that are conducive to disease multiplication. The above can be scraped out. For fish to be happy, they must first be healthy. You can actually tell whether a Koi fish is sick. Indicators may be changed in behaviour such as sudden sluggishness in movement or clumsiness in movement as compared to the original state.

    To check your Koi’s health, you can also observe the physical features of the fish. By this I  mean: the scales, whether they are bright or dull; their tummies – basically anything out of place can hint lack of proper fish health. And when you notice something amiss, be sure to report to the nearest specialists or look it up online.


    So, as you have seen, this is indeed an interesting breed. For more information in management, contact professional aquarium managers. Here is a basic summary of what you’ll be dealing with when you get your own Koi fish:

    Group Type
    Species Cyprinus Rubrofuscus
    Origin Japan
    Aggression Low
    Diet Omnivorous
    Edibility Consumable (yet not commonly eaten)
    Common use Petting
    Lifespan 15 – 35 Years but up to 100 years
    Average cost $50
    Temperature 18 – 24 ⁰C
     Weight 35 Pounds (average)

    Table 1.1 Koi Fish Summary.

    For more information or questions that you might have, feel free to post your questions on our platform.


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