A cold-water fish (Salvelinus alpinus). The Japanese name literally means 'Alps char'.
See also: ホッキョクイワナ (ほっきょくいわな)
Arctic char live in lakes in the Arctic region.
Standard katakana spelling; usually written in kana.
Kanji spelling exists but the word is usually written in kana.
Compound of アルプス (Alps) + イワナ (char, a type of trout). The name likely refers to the fish's habitat in alpine or cold mountainous regions.