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Tosakin
AdvancedNatural monument from Kochi prefecture. Distinctive inverted tail fin is most beautiful viewed from above. Challenging to keep.
Difficulty
Advanced
Temperature
5〜30℃（適温18〜24℃）
Lifespan
5-10 years
Size
10-15cm
Diet
Goldfish pellets (small amounts, multiple times)
About
The Tosakin, sometimes called the Curly Fantail or Queen of Goldfish, is a rare and highly distinctive breed native to Kochi Prefecture (formerly Tosa Province) in Japan, where it has been designated a natural monument. Its most extraordinary feature is the enormous tail fin that, while technically divided, fuses at the center to form a single horizontally spreading fin that curves and ruffles near the water's surface. This unique tail is best appreciated from directly above, and Tosakin are traditionally kept in shallow round basins specifically for top-view observation. The fins are extremely delicate and will deform in even mild water currents, so tanks must have minimal or no filtration flow. Tosakin are gentle in temperament but should always be kept separately from other species to protect their fragile fins. Breeding and maintaining the characteristic tail shape requires considerable expertise, making Tosakin one of the most challenging and rewarding goldfish varieties for advanced hobbyists.
Source: Wikipedia (CC BY-SA 4.0)
Basic Info
Origin
Japan (Kochi Prefecture)
Lifespan
5-10 years
Size
10-15cm
Temperature
5〜30℃（適温18〜24℃）
Diet
Goldfish pellets (small amounts, multiple times)
Care Guide
Tank
Care Specifications
- pH
- 6–8
- Hardness (GH)
- 5–19 dGH
- Water Temp.
- 18–23℃
PeacefulGroupBreeding: Moderate
Sources: FishBase / Aqueon Goldfish Care Guide
Morphs (Varieties)
金魚品種は体型・尾型・鱗・色の選抜固定(line-bred)。出目・透明鱗(キャリコ)・白子等は単一座。
Line-bredEstablished by selective line breeding.
Deep body / dorsal humpReversed / curled tail
Sources: Wikipedia - Goldfish (Varieties) / 金魚 - Wikipedia (日本語版・品種)
A curated selection of notable morphs. Inheritance modes are a breeding-planning guide; actual appearance varies with combos.
References & Sources
Edited & verified by: br-choku editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Taxonomy & Authority
Accepted name: (Linnaeus, 1758)
Synonyms: Cyprinus auratus Linnaeus, 1758, Carassius auratus auratus (Linnaeus, 1758), Cyprinus thoracatus Valenciennes, 1842, Carassius burgeri Temminck & Schlegel, 1846, Cyprinus chinensis Gronow, 1854
Authority databases: FishBase · GBIF · FishBase: Carassius auratus · GBIF: Carassius auratus
Nomenclature follows global taxonomic authority databases.
Tosakin Listings
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