Japanese Rice Fish (Japanese Killifish) Care – Tank Size, Diet, Price & More


The Japanese Rice Fish is a small fish and great for most small aquariums.

. As you may know, these rice fish are schooling fish, so always make sure these fish are in groups of at least 6 or more. They are also pretty hardy as well which means that they should be beginner friendly!


Japanese Rice Fish
By NOZO – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=170001 OLYMPUS DIGITAL CAMERA

These fish are almost translucent and are pretty small. They also seem to have pretty large eyes compared to it’s small body. Because of their small size, they should do fine in small aquariums.

Usual Behavior

Japanese Rice Fish, also known as Japanese Killifish, are a peaceful, schooling fish. Just like tetras, they do best with at least 6 or more. They are peaceful by nature, so they usually aren’t the bullies in the tank. Because of their small size, never add larger and more aggressive fish in the same tank just so that they won’t bully or even hurt the fish.


Despite their small size, these fish can still live for up to 4 years! Always keep these fish in the best of your ability to make sure that they live as long as possible and so that they are as happy and healthy as they can. You don’t want to have dead fish on your hands!


These fish are quite small, only getting around 1.5 inches in length, or around a size of a Neon Tetra. Because of their small size, they will never need a large aquarium.

Japanese Rice Fish Care

Although these fish are hardy, always care for them the best of your ability. They still need clean water and a appropriately sized tank to allow them room to school.

Tank Size

These fish only need a 10 gallon aquarium if you’re planning on a school of 8 or less. They aren’t massive, but if you do plan on getting a larger school, I would recommend to get a larger tank. They are still not large by any means, so they should still be able to thrive in an average 10 gallon aquarium.

Tank Mates

Never keep these fish with larger and more aggressive fish. These fish are pretty peaceful however, so you can keep other peaceful fish and creatures like snails and shrimp.


You can feed these fish foods like …

  • Flakes
  • Pellets
  • freeze-dried foods
  • artemie saline

Water Parameters

All fish need their own water parameters, including Japanese Rice Fish. Make sure to keep stable water parameters so that these fish don’t get shocked or even die from stress.

  • Temperature: 64-75 Fahrenheit (or 17.7-23.8 Celsius)
  • pH: 7.0-8.0

Tank Setup

Japanese Rice Fish enjoy colder temperatures. It’s recommended to have plants in their tank like most common fish should. They need cooler water, so you probably don’t need a heater.

Possible Diseases

These rice fish are generally healthy, but they can still get sick. Always make sure the water is clean and that the water parameters are ideal in the aquarium. Whenever your fish is acting strange, consult your local pet store or go to a fish forum to get help with your fish.

Typical Price

Unfortunately, from the online stores I went to, these fish are not cheap. In fact, just for a school of three, you could pay anywhere from $16-$40 US!

Breeding Japanese Rice Fish

To make sure that they are breeding, you have to meet the specific conditions (like temperature and pH). Plants will help encourage the eggs to get fertilized. Hatching should occur in about 10-12 days. These fish may be harder to sex, but you should focus on the anal fin. Males will have much larger anal fins.

Are Japanese Rice Fish For Me?

The Japanese Rice Fish is a small, beginner friendly fish. This means that they will never need a large aquarium and they also don’t need a heater, which makes them even easier to care for. Just remember to keep their tank clean and that the water parameters are ideal. Also, consider getting live plants if you are getting these fish.

If you’d like to learn more about these fish, check out this article.

Check Out These Articles:

Resources That Were Used About Japanese Rice Fish:

Smart Aquarium Guide

Japanese Rice Fish – Care, Feeding, Breeding, Requirements & Tank Mates

Fish Laboratory

Japanese Rice Fish (Oryzias latipes): Care Guide

Aquatic Arts


Green Water

Japanese Ricefish – Medaka (Oryzias latipes) – Pearl

Arizona Aquatic Gardens


Goldorado Aquatics

Japanese Rice Fish (Oryzias latipes)

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