The main difference between koi and goldfish is that koi grow much bigger and they have barbells (like whiskers), whereas goldfish do not.
The word ‘koi’ comes from the Japanese word ‘nishikigoi’ (pronounced nee-shee-kee-goy). It is a two part word with ‘nishiki’ meaning ‘brocaded’ and ‘koi’ meaning ‘carp’. As a combined word, the letter ‘k’ changes to the letter ‘g’.
Koi are symbols of love and friendship in Japan.