How to Tell the Difference Between Baby Koi and Goldfish?

If you keep goldfish and koi in your pond then they can interbreed because they both evolved from different species of carp. Goldfish were created through the practice of selectively breeding Prussian Carp. Koi were conceived through the selective breeding of the common carp to get their glossy color-schemes. The newbie fishkeeper might struggle to tell the difference between them though.

So do you know how to tell the difference between baby koi And goldfish? There are a few things to look for to tell a baby koi from a goldfish. The koi, even as babies(or fry), have whiskers at the edges of their mouths. These are actually called barbels and all koi have them. This is the best way by far to distinguish a koi baby from a goldfish.  Goldfish have more variety in their shapes than koi can boast. Koi seem to share a very uniform body shape. Of course, if you only have koi in your pond, then the fry are obviously koi. By contrast, goldfish can have different body-types with different tail-fins, head shapes, and body types.

Koi parents will often eat their offspring once they have them so the fry that makes it to adulthood is very lucky indeed. Considering they give birth to thousands at a time means some fry do escape. They survive despite the odds being against them.

Unique Characteristics of Koi and Goldfish

Koi have whiskers, or barbels, that actually function as tasters that they use to find food in sometimes murky waters. They have bright patches of color on their bodies which is why some people call them ornamental fish. 

Goldfish won’t have those whiskers that their distantly-related koi friends have. Even though they were bred from Prussian Carp- goldfish have lost their whisker-features and are considered now a totally different species from carp. The reason that goldfish split off from the koi species and koi didn’t is a mystery to me. I’ll have to leave it to someone else to answer that question.

Size and Shape Differences

Koi have a very similar body structure compared to each other. They are usually long and slender. They will get bigger than your goldfish rather quickly. An adult koi can reach 3 ft. long and a goldfish will only get 1 ft.long.

Goldfish’s bodies will vary more. Some are fat and some slimmer. There are many different types of goldfish including “fancy” goldfish. They have varying colors, fin shapes, and body makeups. Some of the “fancy” types of goldfish sell for a lot of money too just as some koi do.


As the name will tell you, the goldfish’s most common color is gold. As you will soon learn, though, there are other varieties of goldfish that are cloaked in red, white, and black too. The orange-colored “gold” fish pair really well with the white variety of them.

Do you mean to tell me that not all goldfish are gold?

Exactly, the red ones are very popular and you see them in fish tanks all the time. Lesser known ones are black and brown like the Butterfly Tail Goldfish, which is far away from what a newb would think of when thinking of a goldfish.

The coloration of Goldfish usually only consist of one color. At least, the ones most readily available have one or two colors. Fancy varieties of goldfish can have more. That makes them different from koi who usually have all sorts of combinations of reds, blacks, bluish grays,  yellows, and whites on their scales once they start growing. 

The color scheme imprinted across the scales of koi usually determines the type of koi they are. Here are some koi breeds and their distinctive colors and markings.

Kohaku– white bodied(Shiro) with patches of red(hi)

Sanke-Taisho Sanshoku, also known as Taisho Sanke, are also white-bodied with patches of red, but they also have black(Sumi) patterns in them too.

Showa-Like Sanke, Showa Sanshoku, or Showa Sanke are white, black, and red. This often makes people confuse them for each other. Showa has more black-bodied(Karasu) colors than white though.

Utsuri-The actual names of these koi fish are Utsurimono, which translates to “reflections” or “reflective ones”. They have a black body color along with another color that is either hi(red), shiroji (white), or ki (yellow) body markings.

Bekko- Bekko literally means “tortoise-shell” and have bodies colored similarly to Utsuri. The difference id they have black patches or patterns on mostly bright-colored scales.

Asagi and Shusui- Asagi have a blueish-gray color on the top of their bodies with red on the sides.

Some more modern koi such as Ghost Koi only have one color just like their distant gold cousins though. Some of them are black, gold, and white. The gold ones really dazzle against clear water. So they are the exception, so just keep in mind that koi have whiskers (barbels) and goldfish do not. 

Goldfish have their body shapes used to identify them from one type to another. Some of the goldfish types have a similar body shape to koi and others look like little aliens thanks to cross-breeding. Look at the Wikipedia page on goldfish to see the huge differences in goldfish types. 

Hardiness-Who’s the Survivor of the Two?

Koi have the much longer lifespan of the two fish. 

Legend has it that Hanako, who is a koi that died on July 7, 1977, lived 226 years allegedly! He is regarded as the longest living koi-as well as one of the longest living organisms on record.

Generally, most koi live to 50 years and Hanako is just a special case of the perfect conditions being met to allow his incredibly long life. Perfect weather conditions, an ample supply of food, and people knowing when to stop feeding him probably had a lot to do with it. 

Goldfish don’t live close to that. They can live in captivity up to 20 years which is a long time, but not as long as the koi fish.

Some Goldfish Don’t Even Resemble Each Other

Many centuries of cross-breeding has brought forth some very interesting variations of goldfish. Many of them don’t even resemble “gold” fish. Some types can only live in aquariums because they are too far removed from the hardier wild variety.

Koi -have whiskers(best way to tell)

Goldfish-no whiskers

Koi– same general body shape

Goldfish– vastly different body shapes

Koi diet– Omnivorous. Koi eat algae in your pond, also peas, watermelon chunks, and lettuce. They will also eat different waterbugs.

Goldfish-Omnivorous. Leafy greens, broccoli, cooked rice, and bloodworms are some of their favorite munchies.

If you have more great tips that I can add in to tell if it’s a goldfish or a baby koi let me hear them. Leave your reply below or hit up my contact page with your thoughts. Is your pond a goldfish pond or a koi pond? Take these tips listed above to determine just what type of pond you have so you can know how to best keep your fish healthy, happy, and long-living. I enjoy having you as a visitor to my site and hope you stick around for future updates. 

How long do goldfish live? In captivity, goldfish can live up to 20 years.

Where do goldfish live? While many goldfish reside in aquariums throughout the world there are some living in the wild. They require slow-moving water sources and water that is 50F to 76F.

(Weird question alert!)What do goldfish taste like? I don’t know. I imagine you can eat them just like any other freshwater fish though. Let me know if you get brave and try one because I don’t plan on doing this ever.

Will koi eat “fancy” goldfish? They can. The standard goldfish should be fine to keep with koi in a pond, but the smaller fancy breeds of goldfish could potentially be eaten by the much bigger koi.

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Image by cocoparisienne from Pixabay

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