'[3] The common name of the mandarinfish comes from its extremely vivid colouration, evoking the robes of an Imperial Chinese mandarin.

[5][6][7] The similarly named mandarin fish (Siniperca chuatsi), properly known as the Chinese perch, is distantly related.

[8] S. splendidus is one of only two vertebrate species known to have blue colouring because of cellular pigment, the other being the closely related psychedelic mandarin (S. picturatus).

In all other known cases, the colour blue is structural, as it comes from thin-film interference from piles of flat, thin and reflecting purine crystals.

While they are slow-moving and fairly common within their range, they are not easily seen due to their bottom-feeding habit and their small size (reaching only about 6 cm).

In the wild, feeding is continuous during daytime; the fish peck selectively at small prey trapped on coral substrate in a home range of many square meters.

Mandarinfish also have a layer of debatably smelly and bitter slime instead of scales, which blocks out disease and probably also discourages predators, implying their bright coloration is aposematic.