Koi fish are amongst the most popular fish to raise, and they’re certainly pleasing to the eye and for many proud owners - whether in a large tank or a dedicated koi pond in their garden.
What are koi fish and where do they come from? Most koi fish today come from their native Japan, where the word “koi” simply translates to “carp,” which is what they are! Specifically, Japanese koi are a colourful carp which are primarily domesticated for ornamental purposes. It should be clear why: they’re lively and colourful, adding a lovely aesthetic to your home, restaurant, or elsewhere where they’re meant to be seen.
If you’re planning on raising happy and healthy koi fish, here are five quick tips:
01. Make Sure Their Water Conditions are Ideal
Koi are fairly hardy and do well in many conditions, but despite being a coldwater species they prefer a little warmer waters at around 15–25°C. More importantly, koi need to have their habitats filtered out and cleaned frequently to keep them healthy and happy.
Your filtration system should be adequate to flush out and filter the water around 3 times per hour (or more frequently). Around a quarter of the water should be changed every couple of weeks to keep it fresh and to make sure there are enough minerals in the water for them.
02. Give Them Enough Space to Remain Happy & Healthy
There are many different varieties of koi fish and some are fairly small whilst others are quite large (compared to many other common domestic fish species like goldfish). While young koi might only be 6-8cm long, at smallest, many will grow to around 30-45cm in length as adults - jumbo koi can be as long as 90cm long!
You’ll often find online that it’s best to have X number of litres (often gallons) for every cm (or inches) of length of your koi fish. This rule of thumb is pretty good for aquariums, but for private homeowners with smaller aquariums or ponds it might not be too helpful. Instead, consider that one adult koi fish will usually need around 1,000 L (so, a big tank all to himself or ideally, a pond).
If that sounds like a lot of water for a koi fish, well, that’s why so many homeowners keep them in ponds instead. If the pond is about 75cm to 1m deep and sufficiently wide, it shouldn’t be much of a problem to keep a few koi fish happy so long as they have space.
03. Feed Them Well and Often
Koi are omnivorous and are quite happy eating watermelon, lettuce, pellets, and live or frozen food. Feed them twice daily and, if you want, try to teach them to eat from your hand.
04. Keep the Pond Water Clean and Filtered
The water temperature is certainly important for koi fish, as mentioned in the first point above. It’s also important to ensure that the water is kept sufficiently clean and filtered, as well as oxygenated during the hot summer months.
05. Give them Shade and Comfort
Koi are bottom feeders, so they love to hang out at the bottom of your pond or tank. It can get quite hot and the sun can be overbearing for us humans here in Australia, and it’s certainly quite a lot for koi fish, too. Give them some little structures and vegetation to hang out in so they can cool off and keep healthy.
Zen Aquarium
Raise koi fish with fresh live fish and more from Zen Aquarium.