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Home > Goldfish > Tosakin Goldfish: Pictures, Facts, Lifespan & Care Guide

Tosakin Goldfish: Pictures, Facts, Lifespan & Care Guide

tosakin goldfish

The Tosakin goldfish makes a great aquarium addition for collectors of unique fish. This is one of the rarest and most sought-after goldfish varieties in the world, and they are primarily found in their native home of Japan.

The undivided twin tail of the Tosakin goldfish is what makes them special. They are the only goldfish in the world that have this physical characteristic.

Let’s take a closer look at the mysterious beauty of the Tosakin goldfish.


Quick Facts About Tosakin Goldfish

Species Name: Carassius auratus
Family: Cyprinidae
Care Level: Medium
Temperature: 65° to 75° Fahrenheit
Temperament: Friendly and social
Color Form: Orange, orange and white, red and white, red, calico, black, yellow
Lifespan: 10 – 15 years
Size: Maximum 6 inches
Diet: Flakes, pellets, and bloodworms
Minimum Tank Size: Shallow tank approximately 36 inches long
Tank Setup: Aerator, de-chlorinator, and filtration system required
Compatibility: With other Tosakin and slower varieties of fish

Tosakin Goldfish Overview

The Tosakin goldfish is near extinction, so it’s difficult to find outside of Japan. The atomic bombs dropped on Hiroshima and Nagasaki were not only devastating to the people of Japan but had a significant impact on native species, including the Tosakin goldfish, whose numbers dropped to near zero. 1946 brought an earthquake and tsunami, and most people thought that the Tosakin goldfish had gone extinct. But six fish survived. A man named Hiroe Tamura rediscovered the fish in a restaurant and persuaded the owner to trade him the unique fish for a bottle of vodka. Two of the six fish were breeder fish, and he was able to begin repopulating the species. The Japanese government then declared the Tosakin goldfish a protected species.

Goldfish In a tank
Image by: panpilai paipa, Shutterstock

How Much Do Tosakin Goldfish Cost?

The rarity of the Tosakin goldfish makes them expensive. Occasionally, they sell for $80 per fish from some breeders, but it’s not uncommon to see incredibly high price tags attached to them. Quality adults often sell for hundreds of dollars.

Typical Behavior & Temperament

As goldfish behavior goes, Tosakin goldfish are mild-mannered and friendly. Unlike many goldfish species that like to hide in cracks and crevices, Tosakins are happy to float around their tank. They’re not great swimmers, and floating is the method that they use most frequently to get around.

Tosakins aren’t aggressive toward fingers in the water or other fish. They co-exist happily with others and are social animals.

Appearance & Varieties

Tosakin goldfish come in many colors. The most common hue is orange or orange and white. Due to selective breeding practices, there are now many Tosakin goldfish in other colors, like red and white or yellow. Calico and black varieties also exist, but they aren’t as popular as their more colorful counterparts.


How to Take Care of Tosakin Goldfish

Habitat, Tank Conditions & Setup

Tosakin goldfish require a special tank setup that accommodates their poor swimming ability. They need shallow tanks and don’t do well in deep ones. Traditionally, Japanese owners keep Tosakin goldfish in shallow bowls. Fish experts agree that 20 cm or less is the rule for tank height.

Tank Size

Tans should be semi-shallow and wide enough for the Tosakins tail fins and bodies to grow. Goldfish experts recommend that the tank be a minimum of six times longer than the expected adult size. So, for a Tosakin goldfish, the tank should be about 24 inches wide by 36 inches long.

Tosakin goldfish in pond
Image by: Pavaphon Supanantananont, Shutterstock

Water Quality & Conditions

The ideal water temperature for Tosakin goldfish is between 65 and 75 degrees Fahrenheit. The water should be slightly warmer during quarantine periods, ranging from 82 to 85 degrees Fahrenheit. pH should be kept neutral, with an acceptable range falling between 6.8 and 7.5.


Sand substrate is the best choice for goldfish tanks because it improves water quality and the health of your fish by encouraging the growth of beneficial bacteria.


You can add a few plant varieties to your Tosakin goldfish tank, including floating plants like water hyacinth or waterlilies. These plants also help manage water quality.


Aquarium light options include fluorescent, LED, and UV lighting. All are suitable for goldfish and work well as a permanent lighting solution.


A filtration system, heater, and aeration system are necessities for a Tosakin goldfish tank, but you must be careful of their strength. Minimum suction is important because Tosakins can’t swim well enough to avoid being sucked into a filter.

An air-powered sponge filtration system is best because it has enough biological filtration to keep your tank clean and offer oxygen but avoids the creation of a strong current.

Are Tosakin Goldfish Good Tank Mates?

Tosakin goldfish are social beings and can make great tank mates with other species. That said, you can’t pair them with just any fish because of their unique tail structure. Their tail gives them poor swimming skills, so they aren’t compatible with faster goldfish like the common, Shubunkin, or comet.

Tanks with aggressive fish are also a big no-no for Tosakin goldfish. Their slow speed makes them easy prey targets.

Fish that make great tank mates for Tosakin goldfish include:
  • Fantail
  • Ryukin
  • Lionhead
  • Oranda
  • Black Moor
  • Any slow swimming goldfish species


What to Feed Your Tosakin Goldfish

Fish flakes are the easiest nutrition source for Tosakin goldfish because they’re not picky eaters. Choosing appropriate goldfish pellets should be ample for keeping your Tosakin healthy and happy.

We recommend feeding sinking pellets rather than floating ones to make the food easier for your Tosakin goldfish to get to and avoid them developing issues with their swim bladder.

Many goldfish die as a result of improper feeding, diet, and/or portion sizes – which can be easily prevented by proper education.

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Keeping Your Tosakin Goldfish Healthy

Given that the Tosakin goldfish is endangered and descended from a population of only six fish, they have been excessively inbred over time to increase the population. This is the likely reason that they are so sensitive to environmental changes and have physical deformities unique to the species.

Feeding them top-quality food and keeping their environment well-maintained are the best ways to keep your Tosakin goldfish healthy.

Tosakin goldfish are prone to developing swim bladder issues because they are deep-chested. Don’t assume that your goldfish is dead just because they’re swimming upside down. Often the fix is to avoid feeding them for 24 hours to allow them to self-correct. If your fish are frequently having swim bladder issues, changing to a food that sinks and has bloodworms can help.


Breeding Tosakin goldfish is easy, but you’ll have to adjust their environment a bit. They prefer breeding in warm temperatures. Females need to be fed three times a day to get them prepared, and make sure they have live plants or spawning areas in the tank. This ensures that the female has something to anchor her eggs to. Once spawning has occurred, you can move the eggs to a secondary location to prevent them from being eaten.

Are Tosakin Goldfish Suitable for Your Aquarium?

The Tosakin goldfish is truly a gem for goldfish collectors or treasure hunters. These fish are beautiful to watch and definitely a topic of conversation. However, Tosakin goldfish aren’t recommended for first-time fish owners. They require specific care and equipment to thrive.


Final Thoughts

Tosakin goldfish is a rare and unique fish breed with specific care requirements. These fish have a rich and colorful history, but they can be expensive and hard to find. While they aren’t your everyday goldfish, rare fish collectors will be thrilled to have the Tosakin as part of their aquarium.

Other goldfish varieties: 

Featured Image Credit: Sad Agus, Shutterstock

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