鯉 (koi) means “carp” | MotiTan Japanese Dictionary

More examples

子どもたちは池の鯉に餌をやりました。ko do mo ta chi wa ike no koi ni esa o ya ri ma shi ta

The children fed the carp in the pond.

A hardy freshwater fish that grows in still or slow-moving water and is also valued for its striking colors.

池や川などにすみ、ひげと大きな鱗をもつコイ科の淡水魚。ike ya kawa na do ni su mi hi ge to ō ki na uroko o mo tsu ko i ka no tan sui gyo

The word 鯉 (koi, "carp") is an old Japanese term, and the kanji 鯉 was adopted from Chinese writing to represent the same fish.

In English, koi usually means the ornamental varieties of carp bred for their colors and kept in garden ponds, while carp has the broader meaning.