Watonai Goldfish (Care Guide)

exotic japanese watonai goldfish

The Watonai goldfish is known for its unique look, which comes from a mix of the common goldfish and the Wakin. It has a long body and flowing fins and can live in both ponds and aquariums.

Originating from Japan, the Watonai is still relatively rare among fish enthusiasts but is becoming more popular due to its resilience and adaptability.

It’s important for those interested in keeping Watonai goldfish to learn about the best care practices and the specific needs that make this breed thrive. Proper care will not only benefit the Watonai but also add to the diversity of any fish collection.

Watonai Goldfish Essentials

Watonai Goldfish are recognizable by their varied colors and patterns. They can live for more than 15 years, requiring long-term care.

In a pond setting, they may grow to 19 inches, so ample space is necessary for their growth.


Watonai goldfish have a long body and a double ribbon tail that resembles a butterfly from above. Their tails enhance their appearance, making them favored for decorative ponds and large tanks. They come in various colors including red, white, orange, blue, yellow, and black.

Watonai can grow to 10-12 inches in aquariums and up to 19 inches in ponds, so they need ample space. Their body shape and tail design allow them to live well with other calm, similarly sized fish.


Watonai goldfish can live over 15 years with proper care and a well-maintained environment. These fish commonly grow to 10-12 inches, with some reaching 19 inches with tails in ponds.

Longevity requires regular water changes and water quality checks. Their lifespan depends on living conditions, diet, and genetics.

A balanced diet and optimal habitat are key for maintaining their health and coloration.


Size is important for Watonai goldfish longevity. These goldfish, a cross between fantail and Wakin, require space for growth. They average 10-12 inches in length, but pond-raised fish may grow to 19 inches.

Starting at one inch while young, adult Watonai need large tanks or ponds. A spacious environment allows for necessary swimming and contributes to their health and appearance.

Aquarium Setup Essentials

To set up a proper habitat for Watonai goldfish, there are several important steps to follow:

  1. Choose a large enough tank to accommodate their size and activity.
  2. Install a filtration system to keep the water clean.
  3. Add safe decorations and appropriate plants for the goldfish.
  4. Provide a proper diet and adequate lighting to ensure their health.

Taking these steps will help create a suitable and thriving environment for your Watonai goldfish.

Tank Size

A 30-gallon tank is the minimum size recommended for Watonai goldfish due to their size potential. These goldfish typically grow to 10-12 inches and can reach 19 inches in ponds. They require space for their long bodies and double tails. Larger tanks or ponds are ideal.

A spacious tank is necessary for their health, socialization, and compatibility with other goldfish. To support their lifespan of over 15 years, the tank should promote their well-being.

Tank Equipment And Decorations

To maintain the health of Watonai goldfish, their aquariums must include a filtration system, proper lighting, and decorations that meet their needs. These elements are crucial for their survival and for providing visual appeal.

  • Filtration System: Maintains clean water, crucial for goldfish health.
  • Lighting: Imitates daylight, helps plants grow, and enhances fish coloration.
  • Substrate and Decorations: Use smooth, large-grain gravel and flat stones to protect fins. Incorporate driftwood and smooth pebbles for a natural look, which calms fish and onlookers.

Consistent upkeep, including weekly water changes and care for plants and decorations, is necessary to keep the Watonai goldfish environment beautiful and healthy.

Optimal Care Practices

To maintain the health of Watonai goldfish, there are several important steps to follow.

First, provide a varied diet to avoid nutritional gaps and obesity. Goldfish need a combination of commercial fish flakes, pellets, and fresh vegetables such as peas or lettuce. This ensures they receive all the necessary nutrients for optimal health.

Second, it is crucial to keep the water quality high. Goldfish produce a lot of waste, so it’s important to have a good filtration system in place. Regular water changes are also necessary to remove toxins and keep the water clean. Testing the water regularly for ammonia, nitrite, and nitrate levels is also recommended.

Additionally, cleaning the tank regularly is essential. Remove any uneaten food, waste, or debris to prevent the buildup of harmful bacteria. A clean tank creates a healthy environment for the fish to thrive in.

Lastly, it’s important to watch the fish closely and observe any changes in their behavior or appearance. By doing so, you can catch and address diseases early. Look for signs of illness, such as lethargy, loss of appetite, or abnormal swimming patterns. If you notice any of these symptoms, consult a veterinarian who specializes in fish to ensure proper treatment.


A balanced diet is essential for the health of Watonai goldfish. They require quality pellets and flakes, as well as goldfish-specific food for necessary nutrients. Fresh vegetables such as peas and lettuce are also important for their diet.

Feeding them a variety of foods ensures they get the right nutrition, which helps maintain their color and growth. It is recommended to feed them small portions frequently to prevent overfeeding.

Treats like bloodworms or brine shrimp can be given occasionally, but it is important to avoid live foods to prevent parasites.

Water Parameters

Aquarists must maintain specific water conditions for Watonai goldfish to ensure their health. This includes regular checks of pH levels, water hardness, and temperature to match their natural environment. Weekly water changes with treated tap water are necessary to remove chlorine and other harmful substances. Proper tank maintenance allows Watonai goldfish to remain healthy and vibrant.

ParameterIdeal RangeNotes
pH Level6.0 – 8.0Regular checks required
Water Hardness5 – 19 dKHUse testing kits
Temperature60°F – 78°F (15.6-25.6°C)Keep temperature stable

Tank Maintenance

Weekly 30% water changes are essential for Watonai goldfish care.

Choose smooth pebbles, flat stones, and driftwood for safe, attractive decoration.

Remove dead leaves and algae regularly for cleanliness.

Use sturdy plants like Anubias and Java fern, as they resist goldfish nibbling.

Provide consistent lighting for 8-10 hours daily to aid plant growth.

Feed a varied diet to keep goldfish healthy and reduce parasite risks from live food.

Common Diseases

Watonai goldfish are prone to several diseases despite efforts to keep their environment clean. It’s important for aquarists to maintain proper care to prevent and treat these diseases to avoid harm to these goldfish.

Proper Care Guidelines:

  • Conduct regular water changes and provide a balanced diet.
  • Choose safe tank decorations and appropriate plants.

Frequent Diseases:

  • Ichthyophthirius multifiliis (Ich) and Fin Rot.
  • Swim Bladder Disorder and Parasitic Infections.

Personality Traits

Watonai goldfish are known for their peaceful and social nature, making them suitable for shared aquariums. They are gentle and can coexist with other non-aggressive fish, often forming bonds with owners and displaying intelligence.

However, they may nip fins, especially around smaller fish or fin-like objects. To prevent this, it’s important to provide a spacious and well-structured aquarium with hiding places.

These goldfish are also curious and enjoy exploring their environment, which includes interacting with tank decorations and noticing changes. They make interactive pets for both experienced and new fishkeepers.

Watonai goldfish are adaptable and can survive in various water conditions as long as they have clean water, proper food, and enough space. Their durability makes them a good choice for any aquarist.

Compatible Tank Companions

Watonai goldfish, being social and peaceful, do well with other compatible fish like Ryukin, Wakin, and Fantail goldfish. These species have similar needs and behaviors, making them suitable tank mates for creating an attractive and active aquarium.

The ‘Goldfish: Care Guide’ highlights the importance of choosing compatible tank mates. Watonai goldfish are resilient and can also live with certain non-goldfish species. Here are some suitable companions for Watonai goldfish:

  • Bristlenose plecos: They eat algae and keep the tank clean without bothering the goldfish.
  • Weather loaches: They have similar water requirements and are peaceful.
  • White Cloud Mountain Minnows: They are calm and add activity to the tank.
  • Rosy barbs: They are peaceful and get along with goldfish.

These fish add variety and help maintain a healthy tank environment. Watonai goldfish need plenty of space, so consider the tank size when adding new fish. Proper companion selection ensures a peaceful and supportive environment for all fish, similar to their natural habitat.

Reproduction Tips

Breeding Watonai goldfish requires monitoring their behavior and providing a suitable environment for spawning. Recognizing readiness is key, as chasing and courtship dances indicate they are ready to breed. Set up a separate breeding tank with spawning substrates like fine-leaved plants or spawning mops to encourage egg laying.

For successful reproduction, move the eggs to a hatching tank to protect them from adult fish and control the incubation conditions. Keep the water quality and temperature optimal for Watonai goldfish.

Feeding Watonai goldfish a nutritious diet, including high-quality pellets or flakes and fresh vegetables like peas and lettuce, is important for their health, fertility, and spawning readiness.

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