Not to be confused with Mandarin Fish (Chinese Perch). The mandarinfish or mandarin dragonet (Synchiropus splendidus), is a small, brightly-colored member of the dragonet family, which is popular in the saltwater aquarium trade. A lesser-known species, these are probably the single most colorful and vibrant fish I’ve ever seen. The mandarinfish is native to the Pacific, ranging approximately from the Ryukyu Islands south to Australia. Yes! They are definitely the most colourful fish in the world.