Tosakin Goldfish (Care Guide)

unique and ornamental goldfish

The Tosakin goldfish, recognized by its distinctive tail fin that resembles a fan, is a highly regarded breed from Japan. It is admired for its appearance and the intensive care it requires.

The Tosakin is popular among hobbyists for its calming effect in aquariums. Keeping these fish healthy and preserving their unique shape requires a deep understanding of their habitat and diet.

It is crucial to find the right balance between the aquarium’s visual appeal and the fish’s biological needs to ensure their well-being. The challenge lies in adopting the correct practices to maintain the Tosakin goldfish’s health and beauty.

General Characteristics

The Tosakin goldfish is known for its unique tail fin structure and a variety of bright colors, making it popular with hobbyists.

A look at its general characteristics shows its beauty, average lifespan, and usual size.

These details are important for prospective owners to grasp the dedication and space needed to maintain a Tosakin goldfish properly.


Tosakin goldfish have a unique tail that resembles a spread half circle when seen from above. They have a round body, a pointed head, and a deep, egg-shaped trunk. Their fins are full, including a prominent dorsal fin, except for their distinct tail.

They come in colors like metallic red, red and white, black, and calico. The shape and pattern of their caudal fins are key characteristics that set them apart from other goldfish breeds.


The Tosakin goldfish, known for its elegant look, typically lives for about ten years with proper care and the right environment. This Japanese goldfish breed is best kept in shallow water to suit its swimming style.

They are susceptible to health issues like swim bladder problems, so close attention to their health is necessary. High water quality is crucial and achieved through regular water changes to prevent diseases and enhance their lifespan.

A balanced diet is also important for their longevity. With the right care, Tosakin goldfish can live for a decade or more.


Tosakin goldfish have a distinct, short body with a pointed head and wide trunk, growing up to eight inches long. They are smaller than many goldfish breeds and are well-suited to living in shallow bowls, typically 60cm in diameter and 18cm deep.

Their tails are unique, spreading horizontally into a semi-circle shape when seen from above, and they have a developed swim bladder. These features are ideal for the small environment of a bowl, where the Tosakin’s slow growth and notable appearance are most visible.

Aquarium Setup Essentials

Setting up an aquarium for Tosakin goldfish requires attention to key details.

Choose a tank that provides enough room for the fish to move and grow.

Proper equipment and decorations are important for the fish’s health.

Tank Size

For proper Tosakin goldfish care, choose an aquarium that holds at least 20 gallons. They need a shallow tank, not deeper than 20cm/7.8 inches, to suit their unique tail and swimming.

Use a sponge filter for gentle filtration and add an air stone for oxygen.

Regularly clean the tank and test the water to maintain a healthy environment.

Avoid overcrowding to keep the Tosakins stress-free.

Tank Equipment And Decorations

The aquarium setup for Tosakin goldfish should include a filtration system that keeps water clean and has a gentle flow. This will help to maintain a healthy environment for the goldfish.

Choose tank equipment and decorations that are safe for these goldfish. Opt for large, smooth gravel, stones, and driftwood to avoid damaging their delicate tails. It is important to provide a comfortable and safe habitat for them.

In addition to the tank equipment, it is also beneficial to add live plants such as Marimo Moss Balls, Java Ferns, and Anubias. These plants not only enhance the aesthetic appeal of the aquarium but also enrich the habitat without taking up too much space.

To promote the goldfish’s health, it is recommended to use a light with a timer. This will mimic natural light cycles, which is beneficial for their overall well-being.

In addition to the setup, it is crucial to maintain a consistent water temperature. Goldfish are sensitive to temperature changes, so it is important to keep the water temperature stable.

Lastly, provide a varied diet for the goldfish. This should include flakes, pellets, and brine shrimp. A diverse diet will ensure that the goldfish receive all the necessary nutrients for their growth and overall health.

Optimal Care Practices

To maintain Tosakin goldfish health, aquarists must follow these care practices:

  • Provide a balanced diet.
  • Ensure stable water conditions.
  • Keep the tank clean.

These steps help prevent diseases and are vital for the fish’s longevity and vitality.


To ensure the health of Tosakin goldfish, a varied diet with both plant and animal nutrients is critical. Tosakins, being fancy goldfish, require specific nutrition. Here are essential dietary guidelines:

  1. Provide a mix of quality flakes, pellets, and occasional frozen foods like brine shrimp and bloodworms for diverse nutrition.
  2. Add blanched vegetables such as peas and spinach to their diet daily to prevent swim bladder problems and maintain health.
  3. Feed Tosakins small meals two to three times a day, adjusting the quantity based on their appetite to prevent overfeeding and aid digestion.

Water Parameters

Water conditions are crucial for the well-being and growth of Tosakin goldfish. These fish require specific water features such as shallow depth, calmness, and purity due to their limited swimming ability. To ensure the Tosakin’s unique tail forms correctly, keepers typically maintain the water at a shallow depth and keep it still.

Health problems, like swim bladder disorders, can be aggravated by incorrect water conditions. Thus, maintaining proper water depth and cleanliness is essential for both the fish’s health and appearance.

ParameterIdeal RangePurpose
Water DepthUp to 20 cm (7.8 inches)Prevent swim bladder problems
CurrentMinimal to NoneSuit poor swimmers
FiltrationGentleSafeguard delicate fins
Water ChangesRegularEnsure water quality
Bowl ShapeShallow and RoundAid in tail development for these fish

Tank Maintenance

Tank maintenance is essential for the health and longevity of Tosakin goldfish. This includes frequent cleaning, filter maintenance, and water quality checks.

Tosakins require a deep tank with sloping sides to accommodate their curly tail and webbed inner edges, ensuring free movement. The water surface area must be large for proper gas exchange, as Tosakins need a well-oxygenated environment.

Maintaining high water quality is important for these goldfish, which are often bred for shows. Key practices include regular water changes, cleaning the substrate, and keeping the filter in good condition to keep the Tosakin healthy and looking its best.

Common Diseases

Maintaining tank conditions is essential for the health of Tosakin goldfish. It is crucial to manage diseases that can affect these fish, recognized by their elaborate tail and various colors, including metallic red, silver-white, or yellow. Weakness in Tosakin goldfish can result from factors such as intensive breeding.

To prevent diseases, adhere to the following care practices:

  1. Monitor the water regularly to avoid infections, maintaining a consistent environment, particularly after natural disasters like earthquakes and tsunamis.
  2. Provide a balanced diet consisting of quality flakes, pellets, and vegetables to prevent swim bladder problems.
  3. Groom the Tosakin’s unique tail shape properly to avoid deformities, which has been a more demanding task since World War II when the breed almost went extinct.

Temperament Traits

The Tosakin goldfish is calm and sociable, making it suitable for tanks with similar, slow-moving goldfish. Its gentle temperament is important for aquarists considering adding it to their collection. Tosakins do best with their own kind or non-competitive goldfish due to their lack of hardiness against faster or aggressive species.

Tosakins need a peaceful environment because of their ornate tails. They are poor swimmers and require tanks with low water flow to avoid stress and subsequent health problems. They also require stable water conditions, especially in their first year, to support their development.

The Tosakin was bred in Japan by a hobbyist aiming to create a resilient and attractive goldfish after losing other fish to disease. However, Tosakins remain sensitive and are better for experienced hobbyists who can meet their care needs. This includes maintaining a calm tank and careful grooming to maintain their tail shape. Proper care ensures a stable and healthy life for Tosakins.

Compatible Tank Companions

Selecting the right tank mates for Tosakin goldfish is important due to their specific needs and peaceful temperament. Tosakins are distinctive for their curled tail fin, which affects their swimming speed.

When choosing tank companions for Tosakin goldfish, consider the following:

  1. Fancy Goldfish Types: Other slow-moving fancy goldfish make suitable companions for Tosakins. This includes the Ranchu, with a similar shape, the Ryukin, recognizable by its high back and flowing fins, and the Osaka ranchu, noted for its rounded body. Pearlscale and Telescope-eye goldfish are also compatible due to their calm nature and slow swimming.
  2. Avoid Fast Swimmers: Do not pair Tosakins with streamlined goldfish like the common goldfish or comets. These fish are quicker and can compete with Tosakins for food, causing stress and possibly disrupting their balance.
  3. Specific Needs: Tosakins require a controlled environment with high water quality and a suitable tank landscape to protect their fins and gills. They should be kept with other Tosakins or similar fancy goldfish that need the same care level. Avoid fish that require different conditions or exhibit aggressive behavior.

Reproduction Techniques

Reproduction techniques are crucial for the survival of Tosakin goldfish, which are recognized by their unique 118-degree fan-like split tail. Originating from Kochi Prefecture during the Meiji period, Tosakins are now considered national treasures in Japan, necessitating responsible breeding practices.

To breed Tosakin goldfish, a male and female are placed into a separate breeding tank containing spawning mops or plants to catch the eggs post-spawning. The fish are fed nutrient-rich food and exposed to cooler water temperatures to trigger spawning.

After spawning, the adult fish are removed to prevent them from eating the eggs. The eggs are moved to a rearing tank with mild aeration and low light to support proper development. The eggs hatch in 4-7 days, and the fry are fed infusoria or fry food.

Selective culling is carried out as the fry grow, choosing those with the correct tail symmetry and shape. This ensures the Tosakin breed’s standards are upheld. Despite being nearly lost during World War II, these practices have allowed the Tosakin goldfish to prosper.

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