Hepper is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Watonai Goldfish: Pictures, Size, Care, Tank Setup & More

Brooke Billingsley

By Brooke Billingsley

watonai goldfish swimming at the bottom of the tank

While you may think of the goldfish as the cheap fish that kids win at carnivals, you might be surprised to know that there are over 100 breeds of goldfish! Goldfish are the product of careful selective breeding to produce unique and interesting varieties. One variety of goldfish that many people are unfamiliar with is the Watonai. They can be difficult to find, and expensive to boot, so it’s not unusual that you’ve probably never heard of or seen a Watonai goldfish.

Size: 10–12+ inches
Lifespan: 10–15 years
Similar Breeds: Other fancy goldfish breeds, koi
Suitable for: Ponds or large aquariums
Temperament: Social, peaceful, active

If you’re lucky enough to come across a Watonai, you should know that the fish you’re seeing isn’t the original breed. The Watonai breed was developed sometime in the early 1900s, but within 50 years or so, they went extinct. This isn’t unheard of since many animal breeds went extinct during World War 2 and the fallout of the war.

In recent years, breeders have begun working toward bringing the Watonai back. The original Watonai breed was developed by crossbreeding Ryukins, and Wakins, so that is what modern-day breeders are doing. The benefit of breeding these fish now is that we have a stronger grasp of how genetics play a role in the health and hardiness of fish, allowing us to create better Watonai fish than before.

Watonai Goldfish Breed Characteristics

Ease of Care

divider1- goldfish

How Much Do Watonai Goldfish Cost?

Since the Watonai is still a breed in development, they can be extremely difficult to find, especially locally. Some breeders sell their Watonai through their websites, but you should be prepared to pay shipping costs. The cost of a Watonai goldfish can start around $100–$200, but high-quality fish and those with desirable markings can exceed $400–$500!

They are often easiest to find in locations that breed pond fish, like koi. The Watonai is a large goldfish variety, and it has been bred specifically to be viewed in a pond. These fish do best in ponds, as opposed to indoor aquariums, so you should be prepared to invest in an appropriate environment to keep your Watonai happy and healthy.

watonai goldfish in a tank
Image Credit: chrisbrignell, Shutterstock

Sociability of the Watonai Goldfish

Do These Fish Make Good Pets?

Yes, the Watonai does make a good pet. These fish are sociable and active, which makes them fun to watch. They can learn to recognize faces and sounds, so they can familiarize themselves with the person who feeds them. Like koi, Watonai will commonly swim to the water’s surface near the person in hopes of getting a snack.

Does This Fish Make a Good Tankmate?

Yes, the Watonai is a good tankmate for a variety of other fish. They do well with other fancy goldfish, but you should avoid putting them with fancies that have limited mobility due to their breeding or body shape, like the Celestial or Eggfish, since the Watonai will likely outcompete these fish for food. Like most goldfish, these fish will eat smaller tankmates, so make sure to provide plenty of hiding places if you’re planning to keep smaller fish varieties with your Watonai.

watonai goldfish at the bottom of the tank
Image Credit: chrisbrignell, Shutterstock

Care Guide & Tank Set Up

Water Quality & Temperature

High water quality is essential for the health of goldfish, and in a pond, there are specific things that you will need to do to maintain the quality of the water. Removing things that fall into the pond, pond raking, and providing proper pond filtration are all needed to keep water quality high.

Goldfish can survive a wide temperature range, so while they prefer cool water, they can survive in temperatures as cold as just above freezing. As long as they have a pond that is at least 18 inches deep and the surface of the water doesn’t freeze over completely, the Watonai can survive the winter outdoors.


The substrate you select for your Watonai should be something that your goldfish can’t get wedged in their mouth or choke on, which means that gravel and other small pebbles are likely not suitable. Sand and aquatic soil are suitable, but in a pond, you will likely have some form of one of these substrates, as well as smooth river rocks.


Pond plants are ideal companions for the Watonai. Floating plants provide shelter and shade, and they are typically not eaten by goldfish. Water lilies, water hyacinths, hornwort, and water irises are all good options as well.


A routine day/night lighting cycle is all that is required for the Watonai. If your fish live in an outdoor pond, then you likely won’t need to provide any type of lighting except for aesthetic purposes. For indoor fish, a tank light is recommended to ensure the fish receive consistent lighting.

Aquarium light
Image Credit: TIPAKORN MAKORNSEN, Shutterstock


Goldfish are exceptionally dirty fish, and they create a heavy bioload in their environment. Because of this, strong filtration is essential to the health of the Watonai. You may need to enlist the help of a fishpond professional to ensure that your filtration system is strong enough for the fish in your pond. For indoor fish, it’s best to over-filter their tank rather than under-filter it.

goldfish divider

Things to Know When Owning a Watonai Goldfish:

Food & Diet Requirements

The Watonai is an omnivore, and a balanced and varied diet will keep them healthy. Koi and pond fish food can be offered to your Watonai, although a pond goldfish food is ideal. Stick to high-quality foods that contain appropriate nutrients for the season for outdoor fish. Goldfish love treats, including worms, insect larvae, spinach, cucumber, bloodworms, and bananas.

red bloodworms in a pile
Image By: schankz, Shutterstock

Size & Growth Rate

Watonai goldfish can get quite large, even exceeding 12 inches in length in some circumstances. Because of their rapid growth rate and large size, these fish are best kept in ponds or very large tanks. The average home aquarium isn’t large enough for these big fish. When you get a Watonai, you should provide your fish with the space that you would provide to a koi.


While the Watonai is a variety of goldfish all to itself, you can find them in a variety of lovely colors. Red, gold, orange, white, and black are all common colors. They can have bicolor or tricolor markings, with some goldfish even having calico markings that include blue. They can also be Sarasa, which is a bicolor variety that consists of red and white.

Lifespan and Health Conditions

The lifespan of the Watonai is excellent at 10–15 years, but if you want it to be as long as possible, keep an eye out for common fish health conditions.

Minor Conditions
  • Parasites
  • Ich

Serious Conditions
  • Swim bladder dysfunction
  • Dropsy

Male vs Female

Female Watonai goldfish are likely to be more plump and round than males, especially during the breeding season when they begin to develop eggs. Females also have a slightly outward pointing vent, or anal opening, while males have an opening that is flat or slightly recessed into the body. During the breeding season, you can spot breeding stars on the gills and “cheeks” of the male Watonai, but these breeding stars usually are only present during the breeding season and not year-round.



The Watonai is a gorgeous goldfish variety, but they can be very expensive and hard to find. They are rare and should be considered a breed still in development while they come back from extinction, thanks to the efforts of breeders. With proper care, you can expect your Watonai to be with you for upwards of 15 years, and these fish can get very large. They are ideal pond fish, and their hardiness means they can do well, even in harsher environments.

Featured Image Credit: chrisbrignell, Shutterstock

Related Articles

Further Reading

Vet Articles

Latest Vet Answers

The latest veterinarians' answers to questions from our database