Blue Mandarinfish

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. The mandarinfish is native to the Pacific, ranging approximately from the Ryukyu Islands south to Australia.

Taxonomy and etymology
The Mandarinfish was first described as Callionymus splendidus in 1927 by Albert William Herre, an American ichthyologist working in the Philippines.[1] It was later placed in genus Synchiropus. The generic name Synchiropus is from Ancient Greek syn-, meaning "with", and -chiropus meaning "hand-foot".[2] The specific epithet splendidus is from Latin for splendid. The common name of the Mandarinfish comes from its extremely vivid colouration, evoking the robes of an Imperial Chinese mandarin.[3] Other common names include Mandarin goby, Green mandarin, Striped mandarinfish, Striped dragonet, Green dragonet and sometimes Psychedelic mandarinfish.[4] [5] [6] The similarly named mandarin fish (Siniperca chuatsi), properly known as the Chinese perch, is only distantly related.

The Mandarinfish belongs to the perciform family Callionymidae, the dragonets, which counts 10 genera and more than 182 species. Genus Synchiropus counts 51 species, divided into 10 subgenera. The Mandarinfish is in subgenus Synchiropus (Pterosynchiropus) along with the Australian LSD-fish (S. occidentalis) and the LSD- or psychedelic fish (S. picturatus).[7]

Description
To date, S. splendidus is one of only two animal species known to have blue colouring because of cellular pigment, the other being the closely related LSD-fish (S. picturatus). The name "cyanophore" was proposed for the blue chromatophores, or pigment-containing and light-reflecting cells. In all other known cases, the colour blue comes from thin-film interference from piles of flat, thin and reflecting purine crystals.[8]

Ecology
Mandarinfish are reef dwellers, preferring sheltered lagoons and inshore reefs. 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). They feed primarily on small crustaceans and other invertebrates.

Diet
Based on the gut analyses of 7 wild fish Sadovy et al. (2001) determined that the mandarinfish has a mixed diet that consists of harpacticoid copepods, polychaete worms, small gastropods, gammaridean amphipods, fish eggs and ostracods. In the wild, feeding is continuous during daytime; the fish peck selectively at small prey trapped on corral substrate in a home range of many square meters.[9]

Relationship to humans
Despite their popularity in the aquarium trade, mandarinfish are considered difficult to keep, as their feeding habits are very specific. Some fish never adapt to aquarium life, refusing to eat anything but live amphipods and copepods (as in the wild), though individuals that do acclimatize to aquarium food are considered to be quite hardy and highly resistant to diseases such as ich. They cannot contract the disease Ichthyophthirius because they do not have the skin type that this common aquarium disease affects.

The mandarinfish appeared on a 39 kip postage stamp from Laos issued in 1987, and a 40 cent postage stamp of the Federated States of Micronesia issued on 26 August 1993.[10] [11]