We frequently receive a common query from our customers when they buy butterfly koi fish or other koi fish varieties from our store or online: How to successfully breed koi fish at home? Well, fair enough, because without understanding proper breeding techniques, you can put the life of your kois at risk.
At Zen Aquarium, we are the trusted premium koi fish providers across NSW. So, through today's article, we will be sharing everything that you should know about healthy koi fish breeding at home. Also, whenever you plan to buy koi fish in NSW, just trust us, because we partner directly with trusted koi fish farmers and bring you the healthiest and premium varieties of koi fish that too, at affordable pricing.
When Are Koi Fishes Ready To Breed?
Basically, this is pretty easy to understand because your female kois will look visibly rounder, specifically from the belly area. Similarly, for male kois, you will start noticing breeding tubercles on their gill plates and pectoral fins. Some koi owners misinterpret these white tubercles as disease, but this is very normal and part of their breeding process.
Apart from these signs, our customers mostly ask us about the expected timing of the koi fish breeding cycle. Generally, kois breed when the water temperature is 18° to 21° Celsius. In NSW, our water temperature goes to this temperature from October to December. So, you can expect your koi fish breeding process to happen in this particular time period.
How To Set Up Your Breeding Tank the Right Way?
Now, setting up a proper breeding environment is where many people make mistakes when they buy butterfly koi fish and try breeding at home. You need a dedicated spawning tank, not your main pond, because this gives you much better control.
Your breeding tank should be at least 3 feet by 3 feet by 8 feet. Also, please make sure that the water depth is around 45-50 cm. We are stressing on it because the shallow depth of water is really important as it helps concentrate eggs and sperm for better fertilisation rates.
Apart from this, maintain the water temperature at exactly 25°C for optimal spawning conditions. You can use aquarium heaters for this, and we always tell our customers who fish online across Australia that temperature control is absolutely critical for successful breeding.
What Equipment Do You Need for Koi Fish Breeding?
Like any serious koi keeper, you need proper equipment for breeding success. First, you need spawning materials where your female koi will deposit eggs. You can use spawning ropes, brushes, or natural plants like water hyacinth. These materials copy the vegetation where koi naturally lay eggs in the wild.
You can make DIY spawning mops from nylon rope with plastic strips, but commercial spawning brushes work better in our experience. We tell all our customers who buy butterfly koi fish from us that investing in proper spawning brushes makes a real difference.
Your aeration system needs to be gentle with air stones, providing sufficient oxygen without creating strong currents. The water should be really very still during spawning to keep your koi comfortable and properly focused on breeding.
The Spawning Process Step by Step
Before introducing your breeding koi, set up the breeding tank two to three days in advance with clean, treated water, and allow your parent koi to acclimatise for at least 20 minutes before you release them into the tank.
Stop feeding both male and female kois when they are in the spawning tank to maintain water quality. Also, just cover the tank to help your koi adjust to their new environment because this reduces stress and encourages natural spawning behaviour.
Apparently, the spawning behaviour of kois is very noticeable because the males chase females around the tank. You will hear the sound of males nudging and pushing the female koi towards spawning materials. This physical interaction makes the female release eggs while males release milt to fertilise the eggs. You can expect the spawning process to end for about three to six hours. It can look aggressive with males sometimes lifting females partially out of the water, but this is completely normal behaviour.
How To Take Good Care of Koi Fish Eggs?
After spawning ends, you must remove the parent koi immediately. Adult koi do not recognise their offspring and will eat the eggs and babies as food. This is one of the biggest mistakes people make when they try breeding at home.
Fertilised koi eggs are about 2mm across, translucent with a slightly brownish colour. You might see tiny dots or movement inside, showing embryo development. Unfertilised eggs turn milky white and develop fuzzy fungus after a few days, so remove these immediately to prevent contamination.
Soak the eggs attached to spawning ropes in malachite green solution (2 grams per 265 gallons) for 30 minutes. This prevents fungal infections that can kill developing embryos.
Keep water temperature at exactly 25°C during incubation. Koi fish eggs mostly hatch in three to seven days, based on temperature consistency. So, maintain the water temperature at exactly 25° Celsius and continue gentle aeration to provide oxygen without disturbing the eggs.
Some Common Mistakes That Can Kill Your Breeding Success
Many people fail at koi breeding because they make basic mistakes. Never use an inadequate tank size because this leads to poor water quality. Strong filtration will suck up eggs and fry, killing your breeding efforts.
Never attempt breeding with fish under 3 years old. The offspring will be weak, and most will die. Do not try breeding in the wrong seasons or temperature conditions because koi follow natural cycles.
Overfeeding fry causes water pollution that kills them quickly. Not monitoring water quality during critical periods is another common failure point.
Never ever use pond water or normal tap water for the spawning tank, and fill it with fresh water. You can even add methyl blue to disinfect the water for a healthy process.
Zen Aquarium Supports Your Koi Breeding Journey
At Zen Aquarium, we provide ongoing support for customers who want to breed their koi fish at home. When you fish online across Australia from us, you get access to our 15+ years of experience helping customers succeed with koi breeding.
Whether you want to buy butterfly koi fish for breeding or need advice on your current breeding project, we are here to help. Call us at 0478 757 332 or email info@zenaquariumau.com for personalised breeding advice. Our shop opens only on SUNDAY at Paddy's Market, Flemington, from 7 am to 3:30 pm.