Synchiropus splendidus

Lore & Background

The mandarinfish was first described as Callionymus splendidus in 1927 by American ichthyologist Albert William Herre, working in the Philippines. It was later placed in the genus Synchiropus, whose name derives from Ancient Greek syn- ('together') and -chiropus ('hand-foot'). The specific epithet splendidus is Latin for 'bright' or 'glittering.' Its common name comes from its vivid coloration, evoking the robes of an Imperial Chinese mandarin. Other common names include mandarin goby, green mandarin, striped mandarinfish, striped dragonet, green dragonet, and psychedelic mandarinfish. The similarly named mandarin fish (Siniperca chuatsi), or Chinese perch, is distantly related.

The mandarinfish belongs to the perciform family Callionymidae (dragonets), which has 10 genera and over 182 species. Genus Synchiropus contains 51 species divided into 10 subgenera; S. splendidus is placed in subgenus Synchiropus (Pterosynchiropus) along with S. occidentalis and S. picturatus. The name 'cyanophore' was proposed for its blue chromatophores, as it is one of only two vertebrates with blue cellular pigment; in all other known cases, blue is structural, from thin-film interference of purine crystals.

The mandarinfish has a goby-like body shape, though this is the only resemblance. Its vivid coloration includes a bright blue background with swirly orange stripes, a blue-greenish face with bold blue stripes, and large pelvic fins used for 'walking' on the seafloor. The real pectoral fins are nearly transparent and located near the center. The dorsal fin is exceptionally tall in males. Eyes are usually red with black pupils. Varieties include the green mandarin (the described form), the red mandarin (with red pelvic fins and orange areas), and the spotted mandarin (light gray-green with black, pink, and blue spots). Mandarinfish are reef dwellers, preferring sheltered lagoons and inshore reefs. They are slow-moving, bottom-feeding, and reach only about 6 cm, making them hard to see despite being common within their range. They feed primarily on small crustaceans and other invertebrates.

Reader's Guide

The mandarinfish is significant in the aquarium trade for its extreme coloration, but it is considered difficult to keep due to its very specific feeding habits. Gut analyses of seven wild fish (Sadovy et al., 2001) showed a mixed diet of harpacticoid copepods, polychaete worms, small gastropods, gammaridean amphipods, fish eggs, and ostracods. In the wild, feeding is continuous during daytime, with the fish pecking selectively at small prey trapped on coral substrate within a home range of many square meters. Some individuals never adapt to aquarium life, refusing anything but live amphipods and copepods; however, those that acclimatize to aquarium food are considered quite hardy and highly resistant to diseases such as marine ich. They are less likely to contract marine ich because they lack the typical skin type affected by this disease. Mandarinfish also have a layer of debatably smelly and bitter slime instead of scales, which blocks disease and probably discourages predators, implying their bright coloration is aposematic. The species appeared on a 39-kip postage stamp from Laos issued in 1987, and a 40-cent stamp of the Federated States of Micronesia issued on 26 August 1993.

Did You Know?

• The mandarinfish is one of only two vertebrate species known to have blue coloring from cellular pigment, not structural color.
• Its common name comes from its vivid coloration, which evokes the robes of an Imperial Chinese mandarin.
• The mandarinfish has a layer of slime instead of scales, which blocks disease and may discourage predators.
• It was first described in 1927 by American ichthyologist Albert William Herre as Callionymus splendidus.