What Kind of Goldfish is Watonai?
Watonai (Watonai, Carassius auratus var. watonai) is a Wakin-type goldfish variety born from crossbreeding Wakin and Ryukin. The name is said to derive from "Watonai," the protagonist of the Edo-period puppet theater play "The Battles of Coxinga."
The body shape is similar to the Wakin form (streamlined), but the tail fin inherits Ryukin characteristics with three-lobed (sanbi) or four-lobed (yonbi) long tails. Overall, it possesses an intermediate charm—"more elegant than Wakin, more active than Ryukin."
Basic Information
| Item | Content |
|---|
| Breed Classification | Wakin-type (Funa body type, long tail) |
| Tail Shape | Three-lobed/Four-lobed (long tail type) |
| Body Length | 20–35 cm (depending on environment) |
| Lifespan | 10–15 years (with proper care) |
| Difficulty Level | Beginner to intermediate |
| Swimming Speed | Same as Wakin (active) |
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Comparison with Wakin and Ryukin
| Comparison Item | Watonai | Wakin | Ryukin |
|---|
| Body Shape | Streamlined (slightly shorter) | Streamlined (elongated) | Spherical/round |
| Tail | Three/four-lobed (long) | Two or three-lobed | Three/four-lobed (fluttery) |
| Swimming Style | Active, medium speed | Very active | Slow, graceful |
| Hardiness | Very hardy | Very hardy | Relatively hardy |
| Tank Mate Compatibility | Compatible with Wakin/Comet | Compatible with Wakin/Comet | Safest with same type |
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Appropriate Rearing Environment
Tank Size
Watonai is a medium-sized goldfish that grows to 20–35 cm when mature. Long-term care requires adequate space.
| Number of Fish | Recommended Tank | External Filter |
|---|
| 1–2 fish | 60 cm tank (57L or more) | External or top filter |
| 3–4 fish | 90 cm tank (140L or more) | Powerful top filter + sub-filter |
| Outdoor | Trough/lily pad basin (60–100L or more) | Not needed (natural filtration) |
Trough and Outdoor Rearing: Watonai's hardy body type makes it well-suited to outdoor rearing (troughs, lily pad basins). Green water (greenwater) cultivation enhances body color and form development.
Water Quality Parameters
| Parameter | Ideal Range |
|---|
| Water Temperature | 10–28°C (optimal 18–24°C) |
| pH | 6.8–8.0 |
| Ammonia/Nitrite | 0 |
| Nitrate (NO₃⁻) | 40 ppm or less |
| Hardness | 5–20 dGH (soft to moderately hard water) |
Temperature Flexibility: Watonai inherits the hardiness of Wakin-type goldfish and can adapt to a wide temperature range of 10–28°C. However, rapid temperature changes (5°C or more in one day) can cause white spot disease and stress.
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Filtration and Water Quality Management
Goldfish are voracious eaters with high waste output, making powerful filtration essential.
Recommended Filter Combinations
- 60 cm tank: External filter (Eheim 2213 or higher)
- 90 cm tank: Top filter + external filter combination
- Outdoor trough: Natural filtration via aquatic plants and algae + aeration
Water Change Frequency
| Environment | Frequency | Volume |
|---|
| Indoor tank (60 cm) | 1–2 times per week | 30–50% |
| Indoor tank (90 cm) | Once per week | 20–30% |
| Outdoor trough | 1–2 times per month | 20–30% |
In greenwater cultivation, water change frequency can be reduced, but if the green water becomes too concentrated, it can cause oxygen depletion; thin it out regularly.
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Feeding and Food
Watonai is an active swimmer with a hearty appetite, but proper feeding management is important to prevent digestive issues.
Recommended Foods
| Food Type | Characteristics | Feeding Tips |
|---|
| Sinking pellets | Good digestion | Use as staple food |
| Floating pellets | Easy to monitor | Easy to control portions |
| Frozen bloodworms/daphnia | High palatability | 2–3 times per week as treats |
| Dried shrimp/krill | Enhances color | 1–2 times per week |
Feeding Amount: Feed an amount that will be consumed in 2–3 minutes, 2–3 times daily. During winter (water temperature 10–15°C), reduce feeding to once daily or less; below 10°C, stop feeding entirely.
Preventing Digestive Issues: Swim bladder disorder (bloating/buoyancy disorder) can result from overeating floating pellets or ingesting air. Use sinking food and check water temperature before feeding as a habit.
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Tank Mates
Watonai's active swimming behavior makes it incompatible with slower, round-bodied goldfish varieties (Ranchu, Ryukin, Bubble-eye).
Compatible Tank Mates
- Wakin and Comet (equally active swimmers)
- Crucian carp (can also be mixed)
- Loaches (useful for substrate cleaning)
Incompatible Tank Mates
- Ranchu, Ping Pong Pearl (food-stealing risk)
- Bubble-eye and Demekin (eye injury risk)
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Breeding
Watonai are egg-layers that spawn in spring (when water temperature reaches 18°C or higher).
Inducing Spawning
- Keep water temperature at 10–15°C during winter (dormant-like state)
- Gradually raise temperature in spring (April–May) to 18–22°C
- When males are seen chasing females in the early morning, spawning is imminent
- After spawning, separate parent fish from eggs (parents will eat eggs)
Fry Rearing: After hatching, wait 3–5 days for the yolk sac to be fully absorbed, then feed infusoria and brine shrimp. When fry reach 3–5 cm, transition to finely crushed adult food.
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Common Diseases and Prevention
White Spot Disease (Ich): Small white spots appear on the body. Develops during water temperature stress or immune suppression. Raise water temperature to 28–30°C to manage (folk remedies using red chili peppers are also used).
Tail Rot: Tail fins deteriorate into tatters—a bacterial disease. Stress and poor water quality are triggers. Treat with Green F Gold medication bath.
Swim Bladder Disorder: Caused by digestive issues or swim bladder malfunction. Overeating floating pellets and sudden temperature changes are common causes. Prevention involves adjusting diet and stabilizing water temperature.
Dropsy (Pine Cone Disease): Scales stand upright—a serious bacterial disease. Early detection and treatment are critical. Recovery is often difficult, but treatment with Green F Gold or Elbaage medication bath should be attempted.
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Outdoor Rearing and Trough Management
Watonai's hardy body type and the cold-tolerance of Wakin-type goldfish make it exceptionally well-suited to outdoor rearing in troughs and lily pad basins.
- Summer: When water temperature exceeds 30°C, use shade nets or bamboo screens to block direct sunlight
- Winter: Can survive winter even if ice forms, as long as the bottom doesn't freeze completely. Continue aeration
- Green Water (Greenwater) Cultivation: Phytoplankton serves as a nutrient source and enhances body color. Water changes can be reduced, but regular water quality checks are necessary
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Watonai is a well-balanced goldfish variety that combines the hardiness of Wakin with the elegant long tail of Ryukin. Despite being easy to care for, it has limited distribution, so spotting one in a shop may be a rare opportunity.
This variety can be enjoyed in both indoor tanks and outdoor troughs, making it an ideal choice for anyone wanting to expand their goldfish-keeping experience. Watch this breed swim actively with its flowing tail in your own tank and enjoy the beauty it brings.
