Koi Goldfish Hybrid
Guide to Understanding and Successfully Breeding Koi & Goldfish

We are going to submerge ourselves into a MIND-BLOWING article as we dig into breeding koi and goldfish.
In the goldfish world, it can’t get any more intriguing than this!
Your average fish pond that graces landscapes are full of what most perceive to be koi or goldfish.
Little do they know that if both types of fish are in the pond, there will most likely be a population of hybrid fish among them.
Before we dive into breeding koi and goldfish, it helps to understand more about the two.
Are koi and goldfish the same thing?
We are excited to answer this question with a plausible, “NO!”
Although they look alike with features but have different body sizes, they are not the same kind of fish.
They both originated from the carp family, but the TYPE of carp they came from is what sets them apart.
Let’s take a look at what sets these two fish apart!

The Differences in Koi and Goldfish
Koi Fish
Originated from: Common carp
Physical Characteristics:
Size 36”
Distinguishing Features
- 2 sets of barbels (whiskers) near mouth
- More variation of colors
- Colors are vibrant
Body Shape
One common shape
Rounded nose
Slim-elliptical body
Cost: $25 - $1.8 million! |
Lifespan: 25-35 years |
Care: Environment
Feeding
|
Spawning: Once a year |
Behavior: Friendly but will eat small things such as smaller fish. |
Goldfish
Originated from: Prussian carp
Physical Characteristics:
Size 6-10”
Distinguishing Features
- Less variation of colors
- Color vibrancy limited to certain varieties
Body Shape
Egg-shaped and Streamline-bodied
Blunt nose
Rounder body
Cost: $5-$50 |
Lifespan: 5-10 years |
Care: Environment
Feeding
|
Spawning: Twice a year |
Behavior: Friendly |
The most expensive koi in the world brought a whopping $1.8 million dollars!
What does Koi-Goldfish offspring look like?
The offspring of koi and goldfish have interesting features. There are characteristics to look for when trying to identify a koi-goldfish hybrid.Breeding Koi and Goldfish

Warm pond water encourages spawning.
Unless you are monitoring your pond continually, you may not be aware when spawning occurs.
A significant indicator of spawning is a foam-like film on the surface of your pond water. You may also notice a strong fishy smell.
So, you are interested in breeding koi and goldfish?
Let’s take a look-see on an easy DIY breeding setup and system.
Easy DIY Koi-Goldfish Breeding
The key to successfully breeding koi and goldfish is to get to the eggs before one of them devours them.
The spawning season generally occurs when the water temperature spikes during the summer.
Plan ahead and have everything in place before your fish spawns.
Preparation
1. Set up a Separate Pool for the Eggs
You can use a small swimming pool, stock tank, IBC container, old bathtub, etc.
Install a filter system.
Cover your pool to prevent birds from eating your daphnia as well as dragonflies and other insects from laying eggs.
Fill with water and allow it to sit for a few weeks until algae has formed.
Add daphnia (live) to water. Daphnia are basically water fleas. They will provide an endless source of food for your fry after they hatch.
You will need to feed the daphnia every 4 days from this point forward.
Sprinkling active dry yeast over the surface of the water will keep your daphnia fed and happy.
Daphnia reproduces at an exponential rate, so you never have to worry about restocking.
2. Place either a spawning mop or egg media in your fish pond to catch the eggs.
Wait and Watch

There is a tale-tell indication that your fish have spawned.
A foam-like film covers the water, and a strong fishy smell may be present.
If you notice this, it’s time to check the pond for eggs.
Transfer the Eggs
- Transfer the eggs to your pool.
- The eggs will hatch 5-7 days after they have been laid.
Caring for the Fry
- Ensure that your pool cover stays on. Birds will feast on your fry if not covered.
- Routinely test your water parameters. Pay attention to the nitrite and nitrate levels.
- If you want to add pellets to their diet, you can feed them small pellets once a day.
- Your fry will need to remain in the pool for at least 1 month or until they reach 3” before they can be transferred to the pond. Some experts recommend that you keep fry separate from adults for up to a year.
And there you have it!

If you have a koi pond stocked with goldfish and koi, you now have a fairly simple way to breed them.
To be successful, you have to scoop up the eggs before they become dinner for mom or dad in the pond.
If you can do that and transfer them to the pool in time, you will have an awesome time watching the process of fish hatching to growing up.
Good luck and we hope you have many fry in your near future!