In Japanese, when distinguishing between biological organisms, it is customary to write them in katakana.

For example, the biological organism referred to as "人間 / human" is always written as "Hito / ヒト" in katakana.

However, in the case of food products, there is sometimes a convention of writing them in kanji.

For example, in the case of the character for "fish /魚 ," the meaning of the fish is embedded in the kanji (example: 鰻 / eel), which can make it seem more appetizing.