Do Koi Fish Have Teeth & Can Koi Bite You

do koi fish have teeth

Koi become family pets.  Often with names and develop a solid connection with their owner. Over time the fish start to recognize people and their movements. You can even feed koi with a bit of practice and time by hand. 

Feeding koi by hand can be the best part of a water feature.  

Before you start putting your hand close to a koi’s mouth, you might be wondering if it is safe and if koi have teeth that can harm you.

Good question, and let us dive in.

Do Koi Have Teeth?

Yes, they do have teeth. Koi teeth are located in the rear of their throat (so you will most likely never see them) and are not used to kill prey.  They use their teeth to chew food, and there is no risk of being bitten.

Koi teeth are called pharyngeal, shared in a range of freshwater fish such as loach and goldfish, making them pharyngonathus (just a fancy way of saying a fish that chews).  

Koi are from the carp family, bottom feeders, and use their teeth to process food hard for them to chew/grind.  Voracious eaters will suck up just about anything and try and eat it, which could be insects, snails, plant roots, tadpoles, or even baby fish.

Food starts to get processed by the gill slits, and gill rakers trap the food and make it available.  A bony part of the pharynx called the “carp stone” helps with chewing.  

Expandable intestines function as a stomach even though koi do not have guts technically.  

Suppose you want to geek out about what makes koi fish function. Check out our page about the internal anatomy of koi fish.

Be careful not to over-feed koi during cold parts of the year as their metabolism starts to slow as the water cools.  Sometimes almost completely halted.  If given too much food during this period, the food sits in their intestines and rots.  Causing health issues. 

Monitor water temperature to know when to stop and start feeding koi.  

Here is a Video Showing Koi Teeth

This video is of a pond owner cleaning their pond and finding a tooth from larger koi.  Usually, you can find them in your pond filter box or bottom sludge if you’re doing a clean-out.   Generally, the teeth don’t cause any issues unless you have a large number of koi in your pond.

Koi shed their old teeth (perfectly normal) and can have up to 30 plus sets in their lifetime.

You can usually spot this if they are on the bottom shaking for a couple of days. Then, they won’t eat for a couple of days due to teeth loss. 

Are Your Fingers Safe if Koi Bites You?

While koi can get pretty big and be intimidating, there is not much risk of being bitten.  

Their mouths can be pretty muscular from all that grinding and chewing. If your finger gets into their mouth, you might feel a slight “pull,” but there is no risk of damage from the teeth since they are small and located pretty far back in their throats.  

The fish are just looking for more food and not trying to bite you.  

Your finger isn’t on their list of favorite food.  So rest assured you are safe and can continue to hand feed if you like. 

Will Koi Attack Another Fish?

Generally, koi do not attack other fish, but some research showed koi attacking fancy goldfish.  This is most likely during mating season, when male koi can become more aggressive.  Not causing any significant damage due to the teeth in the rear of the throat, but could cause tears in the goldfishes skin, which could cause disease.