black carp; black koi
Refers to the wild-type common carp (Cyprinus carpio) with dark coloration, as opposed to ornamental koi varieties. Used in contexts of fishing, aquaculture, and biology.
Black carp are often caught in this river.
The black carp is considered the original species of the ornamental koi.
Standard kanji spelling for the wild-type black carp.
Kana spelling is common in everyday writing, especially in non-specialist contexts.
Compound of 真 (ma, 'true, pure') and 鯉 (koi, 'carp'), literally 'true carp', referring to the original wild form.