Males have more orange colouration in their face and are larger in size with an elongated first dorsal spine. Females have smaller dorsal fins.
Mandarin fish are distinctive due to their unusual shape and broad, depressed head.
One of its most remarkable features is their big outward-set eyes. This is an ideal adaptation for food hunting and feeding in the dim light environments underwater.
They swim with a rapid pulsating of their fins which tends to make them look like they are hovering, like a humming bird.
The mandarin fish is one of the few marine fish which does not have scales. As a protective compensation it is protected by a mucous-coated slimy and smelly skin, which not only protects them from most parasitic skin diseases, but also discourages predators due to its horrible taste. Their bright vivid coloration also serves to give out warning to predators of their nasty smell and taste.
There is little information on specific predators of this species, although scorpionfish are known to lie in wait to attack an unsuspecting mandarin fish, normally during the mating ritual.