Koi For Beginners

Koi for Beginners

Watching Koi gracefully swimming in your beautiful water garden or aquarium is a true delight. No wonder so many people around the world are fascinated by these living jewels. Before you dive into the exciting world of Koi keeping though, there are a few things you should think about. The information you can find on the topic might be easily accessible and as plentiful as you wish but it’s often discrepant enough to make you confused. So it would probably be best to start simple, with the general factors to consider before getting any pet:


Choosing your first Koi

Are you familiar with the different Koi varieties?  As you can see, there are quite many of them but you could start by reading about the most popular ones – Kohaku, Showa, Sanke, Shiro Utsui, Asagi and so on. This would give you an idea what to expect from each variety in terms of colors, pattern, size and more.

Once you select a variety (or varieties), you need to make another decision – where to buy your new Koi from. You can visit a nearby farm and take a look at the fish and the conditions there. Make sure the premises and ponds/aquariums are kept clean, there aren’t bad smells (while a faint “fishy” smell is normal, smells reminding of decay or Ammonia are certainly not) and fish are not overcrowded.

Young, small Koi (around 10-12 cm in length) are perfect for a beginner, as they are less expensive, and the owner has the opportunity to watch them grow into living works of art. Before you make your final decision though, observe the fish for a while – check for unusual behavior or signs of possible illness– flashing, jumping, fin twitching, gasping, red ulcers, white fuzz, specks or lumps, etc. If everything is in order, you can carefully transport the fish to their new home (don’t forget to place them in a separate quarantine tank for 21 days before introducing them to their permanent pond or aquarium).

 Setting up a pond (or an aquarium)

Koi can be kept in a fiberglass or acrylic aquarium, provided it’s large enough. Keep in mind that overcrowding is too stressful and harmful for Koi’s immune system and general health. Additionally, it reduces the biological filters’ efficiency, which can make the living conditions of your Koi even worse. Make sure you provide each individual with enough personal space – each Koi requires at least 50 inches per 1000 gallons of water. This applies for a Koi pond as well. The aquarium is a good option for Koi up to 6 inches long (2 years old) – after that, they would need more room to swim and grow. Place the aquarium out of direct sunlight, in a quiet area. Provide it with a few inches of substrate (a mixture of gravel and rocks would be enjoyable for your new Koi). To ensure ideal water quality, install a high-quality filter and a water heater.

If you want a Koi pond in your park or garden, consider all key aspects before the construction takes place. The pond should be safe for its inhabitants, and easy for you to maintain. One of the most common mistakes, made by beginners, is building a pond, which quickly becomes too small and shallow to accommodate their grown Koi, or any new fish they like to add later. According to experts, a good pond should be no less than 4 foot deep, 7 foot wide and 8 foot long, containing approximately 1500 gallons of water. The right proportions would allow your Koi to reach their full potential both in growth and longevity. By designing the pond deep enough, you protect your swimming jewels from potential predators, as well as from the scorching sun. If it’s possible, choose a shaded or half-shaded location. The pond could be under a tree (not pines and other conifers with needle-like leaves though, as they might block the filters).

Make sure that there aren’t corners or sharp objects that could injure the fish. And finally – aeration and circulation are vitally important for Koi, so don’t forget to include a waterfall, airstone or some other form of aeration to the design. Don’t introduce new Koi to the pond straight away – it needs approximately 30 days to establish a stable eco-system.

After you bring your new Koi home, the adventure truly begins. Taking care of them is fairly easy, and so is providing the right conditions:

 Water quality

Water quality is essential for keeping healthy and happy Koi. To maintain its perfect condition, invest in a good filtration system, including these main components: a bottom drain, filters, pumps, skimmers and UV lights. Choose every component carefully, so it fits your needs and the characteristics of your pond. Naturally, if your Koi live in an aquarium, you won’t need all of these.

The ideal pump should be quiet, highly efficient and reliable. It’s practical to spend a bit more on a high-quality pump and a bit oversized filter, as higher efficiency would cut your expenses in the long run (you would pay less for electricity, won’t need to purchase new ones anytime soon, and most importantly, your Koi would be in good health).

Make sure the water is well aerated. Don’t forget to regularly test the water’s pH levels (you can easily do it with the help of a test kit), and maintain them neutral and stable, between 6.8 and 8.2, with 7 being ideal. Both higher and lower levels are dangerous to Koi. Check the level of ammonia as well – it shouldn’t be higher than 0.25 ppm (parts per million), or even preferably – 0 ppm, as it’s extremely toxic and might poison the fish. Koi release ammonia in the water, and it’s also accumulated by uneaten food and decaying organic debris, which is why the proper cycling and filtering are necessary. Temperature is a key factor as well – Koi handle best stable temperatures, between 65 and 75 F degrees. Extensive temperature swings should be avoided.


One of the ways to ensure the well-being of your Koi is to provide them with high-quality, balanced food, created for their specific nutritional needs. There are different types of food, meant to enhance growth, health or color. Ingredients such as spirulina and carotene enhance color, while wheat germ for example is used for its nutritional and digestive value.

You will soon find that feeding you Koi is a thrilling experience. Never overfeed them, though. Even if they seem to enjoy an extra sipping, you’re not doing them a favor, as overfeeding damages the liver and other internal organs. The excess food in their pond/aquarium can also lead to a fast decrease of the water quality, causing additional health problems. Moderation is the key.


Regardless of the location of your Koi pond, there might be more predators around than you could imagine. Birds, Dogs, Cats, Cayman's kingfishers, otters and opossums are just some of the animals depending on your locality that could pose a threat to your fish. Small, shallow ponds make Koi easy prey but if they have enough room to escape or hide, the hunt would be much more difficult and most predators would simply give up and go elsewhere. Some people like to use flowers to decorate their ponds, and build plant shelfs for them. However, keep in mind that shelves can provide a good opportunity for predators to come close enough to the fish.

There are many different ways to protect your pond – netting, fencing, using decoys or repellents, and mainly, providing enough room for Koi to escape in the deep. If you keep your Koi live in an aquarium, don’t forget to set up a suitable cover, to prevent them from accidently jumping on the floor. It would also guarantee your other pets stay at a safe distance.