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Tosakin Goldfish: Care Guide, Varieties, Lifespan, Pictures & More

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By Lindsey Stanton

Tosakin or curly fantail goldfish_Sad Agus_shutterstock

If you’re a collector of rare and unique fish, the Tosakin Goldfish might be a great addition to your home. They’re considered to be one of the rarest and sought-after goldfish in the world; however, they’re seldom found outside of their native Japan.

What makes this variety so special is its undivided twin tail. In fact, the Tosakin is the only twin-tailed goldfish in the world whose tail is undivided. From a side profile, they look like most other goldfish. But when viewing them from above, you can see their full beauty and unique fanned tail.

Let’s take a closer look into the rare, mystic-like beauty of the Tosakin Goldfish.aquarium plant divider

Quick Facts about the Tosakin Goldfish

Species Name: Carassius auratus
Family: Cyprinidae
Care Level: Medium
Temperature: 65°–78° F
Temperament: Social and friendly
Color Form: Orange, orange and white, red, red and white, yellow, calico, black
Lifespan: 10–15 years
Size: Maximum 6”
Diet: Pellets, flakes, and bloodworms
Minimum Tank Size: Shallow tank 36” in length
Tank Set-Up: Dechlorinator, aerator, and filtration system required
Compatibility: Can live with other Tosakin and some slower variety fish
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Tosakin Goldfish Overview

One of the reasons why you won’t find the Tosakin Goldfish easily outside of Japan is because of its near extinction. The heavy bombing events of Japan during WWII were cataclysmic for the Tosakin Goldfish. It dropped their numbers nearly to zero. And after the 1946 earthquake and tsunami in their home region, they were believed to have gone extinct.

In fact, just six fish had survived. They were rediscovered by a Japanese hobbyist, Mr. Hiroe Tamura, in a restaurant within the Kochi Prefecture. Mr. Tamura was able to persuade the shop owner to trade the fish to him for a single bottle of sweet potato vodka. Fortunately, among the restaurant fish were two breeder fish and four two-year-olds who went on to continue breeding. They were shortly declared natural treasures of the prefecture and protected by the Japanese government.

It is now thought that every single Tosakin Goldfish today is a direct ancestor of those six restaurant survivors.

This goldfish is also known as the Peacock Tail or Curly Tailed Goldfish due to its distinct tail. Some enthusiasts claim the fish to be the Queen of All Goldfish, with the variety taking the kingly title.

How Much Do Tosakin Goldfish Cost?

Being as rare as they are, these goldfish can become quite expensive. Some breeders and fisheries will sell them as low as $80 per fish. However, it’s not uncommon to see them go for much higher. A quality adult fish may sell for hundreds of dollars each!

If you are interested in acquiring a Tosakin Goldfish, you should first communicate with a specialist goldfish society or reputable fishery.

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Typical Behavior & Temperament

A Tosakin Goldfish

Tosakin Goldfish are an extremely mild-mannered variety of goldfish. Don’t expect to see them constantly darting in and out of crags and crevices. Instead, you’ll find them content to float by lazily. They’re not the best swimmers, so they just tend to take it easy.

They’re also not aggressive towards other fish or the fingers that feed. They are rather social and would be happy with other Tosakin in their tank.

Appearance & Varieties

The Tosakin Goldfish can come in a wide array of colors. The typical color for these beauties is an orange hue or orange and white pattern. However, due to selective breeding, this fish can portray itself in other bright colors such as red, red, and white patterned, or yellow.

You’ll also see calico and black varieties for sale. However, these particular Tosakin aren’t nearly as popular as their colorful counterparts.aquarium plant divider

How to Take Care of Tosakin Goldfish

Habitat, Tank Conditions & Setup

The Tosakin Goldfish isn’t just unique in its appearance. They require a special tank setup as well. Since they are very poor swimmers, they don’t do very well in deeper aquariums or tanks. Traditionally in Japan, these fish were kept in large, shallow bowls that were believed to help with the development of their tail.

This belief has since been disproven through modern farming techniques. However, expert keepers all agree that 20 cm or less is the rule for tank height.

You’ll also want to set your Tosakin Goldfish up with a filtration system, aeration system, and a heater (as necessary). But you need to look into the power each of these systems puts out. They should only minimally affect the water they’re in. If the suction is too strong, it could affect your fish’s swimming or be dangerous for them.

If you're a new or even experienced goldfish owner who is having issues understanding the intricacies of water filtration, or just wants a bit more detailed information on it, we recommend that you check out our best-selling book, The Truth About Goldfish. 

The Truth About Goldfish New Edition

It covers everything about creating the most ideal tank setup and more!

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Are Tosakin Goldfish Good Tank Mates?

When it comes to other fish, this species makes for a great tank mate! They’re mild-mannered, friendly, and even sociable. However, you can’t just pair them with any fish because of their unique tails.

Tosakin goldfish_Pavaphon Supanantananont_shutterstock
Image credit: Pavaphon Supanantananont, Shutterstock

In general, fancy goldfish aren’t very strong swimmers—and it’s even more difficult for the uniquely-tailed Tosakin. This means that they aren’t going to be able to compete with faster goldfish varieties such as the Common, Shubunkin, or Comet.

However, they shouldn’t have any difficulties thriving if sharing a tank with Fantail, Ryukin, Lionhead, Oranda, Black Moor, or any other slow-swimming goldfish species. Also, make sure you’re not adding them into an aquarium with an aggressive species either. Their speed turns them into excellent targets.

What to Feed Your Tosakin Goldfish

Feeding your Tosakin Goldfish is super easy. They’re not too picky about their food. Choosing the right pellets or flakes should be ample enough to keep them well-nourished and happy.

We recommend Cobalt Aquatics Ultra Goldfish Color Slow Sinking Pellets. These pellets contain everything that your Tosakin will need to keep healthy and strong. They’re also slow sinking to help your Tosakin feed and get their fill.

Keeping Your Tosakin Goldfish Healthy

Since the entire population of Tosakin can be traced back to six individual fish, tons of inbreeding was involved. This is believed to be why Tosakin Goldfish have unique deformities and are relatively sensitive. You need to ensure that they are being fed top-quality food and that their environments are maintained within proper parameters.

Tosakins are also prone to swim bladder issues since they are deep-chested fish. If you see your Tosakins begin to float upside-down, there’s no reason to assume they’re deceased. It could just be a swim bladder problem. The best fix for this is to not feed them for 24 hours. This will allow the problem to self-correct. If you notice this happening frequently, swap over to a food that sinks immediately and offer bloodworms as well.


Tosakin Goldfish can be bred relatively easily. However, you first need to set the mood. They prefer to breed in warmer temperatures. So, if you plan on breeding during cooler times, you may want to employ the use of a gentle heater. Remember, don’t thermal shock the water too much. Tosakins are delicate.

Once you’ve reached a warmer temperature, you’ll need to start feeding your female three times a day. This will prepare her for the breeding process. Also, you’ll want to ensure you add some live plants or a spawning mop into their pond. This is because they will likely anchor their eggs to something while spawning. After spawning is complete, you can then remove the eggs to a secondary container to prevent hungry adults from getting a quick snack.aquarium plant divider

Are Tosakin Goldfish Suitable For Your Aquarium?

If you’re a true collector and goldfish lover, the Tosakin is one of those grail searches. They’re stunningly beautiful and amazing to watch and observe. However, this isn’t the ideal fish for a first-time owner. They require specific care and equipment to ensure they have the best opportunity to thrive.

Featured Image Credit: Sad Agus, Shutterstock

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