News / Species Spotlight / Revisited - Mandarin Gobies (10/25/11)

Revisited - Mandarin Gobies

by Kevin Gaines


Class: Actinopterygii (ray-finned fishes)
Order: Perciformes (perch-likes)
Family: Callionymidae
Genus: Synchiropus
Species: splendidus


The Mandarinfish belongs to the group of fishes referred to as Dragonets. This group is characterized by having a large head (relative to their body) and reaching sizes of less than 4 inches. They are famous for having some of the most beautiful and distinct color patterns found on any marine fish. Most of the specimens for the aquarium trade belong to the genus Synchiropus. They are scale-less and produce copious amounts of mucous when threatened. It is believed that this mucous is toxic to potential predators. Dragonets are further characterized by having small, pointed mouths. S. splendidus is the most popular and is often called the psychedelic mandarin, referring to the robe of an ancient Chinese mandarin. The common name "mandarin goby" is misleading, due to its resemblance to gobies. Sexual dimorphism is present in this species with males having a longer first dorsal spine as compared to females. Males also grow larger than females.

Natural Habitat

S. splendidus commonly inhabits inshore reefs and protected lagoons. They are usually found in small groups that have a limited territorial range. It is believed that mandarinfish spend much of their life in an area less than 10' x 10'. Distribution is mainly within the Indo-Pacific and covers a vast area from southern Japan to Australia. Due to its cryptic behavior, S. splendidus is very difficult to see or photograph in the wild. Mandarinfish feed on small crustaceans and other benthic zooplankton. It has been reported that a percentage of S. splendidus are caught with drugs, due to their collection difficulty. This certainly may contribute to some mortality experienced in the trade and consumers are encouraged to always use reputable suppliers.

Aquarium Care

There have been a number of articles written on this somewhat controversial aquarium species. Many believe that S. splendidus should not be collected due to its "fragile" nature. It has been my experience that the mandarinfish does very well in the home aquarium when they are provided with the proper diet and habitat. The feeding mechanism of the mandarinfish is much like a seahorse and they often get out competed when kept with more aggressive feeders. They do quite well in a refugium and in larger established tanks. This is due in part to the natural levels of amphipods found in older, more heavily aquascaped aquaria. Some aquarists use turkey basters and other target feeding regimes to keep their mandarinfish healthy. They commonly eat frozen brine shrimp (should be enriched with vitamins), Nutramar Ova, mysis shrimp and a variety of other prepared diets. Keep in mind that larger foods should be chopped, due to their small mouth. It is important to note that only one male per tank should be attempted. Even in large aquariums, males will constantly fight and chase each other usually resulting in one fish dying. A male and female will do well together and some aquarists even keep one male with a couple of females.

Spawning in the reef aquarium is common once a pair has been established. Larval rearing has been extremely limited due to very small eggs (<1 mm) and subsequent larvae. Spawning behavior is characterized by the male and female displaying their large dorsal fins and beginning to swim to the surface while encircling each other. This lengthy courtship culminates in the release of sperm and eggs into the water column under dimmed lighting or shortly after the lights go off.

When friends come over to see your aquarium, it is usually the mandarinfish that gets the most attention. The undulating pectoral fins combined with the paisley swirls of green and orange are absolutely spectacular. Mandarinfish swim in short little bursts, perching on rocks like a bird bouncing from branch to branch on a tree. It is a most unusual fish that has its place in the reef aquarium.