noun
ranchu; ranchu goldfish
A fancy goldfish variety with a rounded body, no dorsal fin, and a fleshy head growth (wen). Often kept as an ornamental pet.
ランチュウは金魚の高級品種の一つです。
The ranchu is one of the high-grade varieties of goldfish.
祖父は庭の池でランチュウを飼っている。
My grandfather keeps ranchu goldfish in the garden pond.
The name ランチュウ is believed to derive from the Chinese reading of 蘭鋳, though the exact origin is uncertain. The kanji 蘭 (orchid) and 鋳 (casting) are ateji, chosen for their sounds rather than meaning.