Form and Function

Synchiropus splendidus has a unique body form compared to other species. Instead of scales, the mandarinfish has a thick outer mucus and slime covering (Fish Species 2006). This is very helpful to the fish because it protects them against parasites and infection, as well as allows them to better move through water and ward off predators (Fish Species 2006). They have a uniquely foul odor and taste which makes them an unpleasant meal for bigger fish and other predators (Patel 2006). Additionally, mandarinfish have sacciform cells on their skin (Aquatic Community 2008, Patel 2006). These cells produce and release toxins to defend againist potential enemies. This is a huge survival adaptation for the small fish that cannot physically fend off or outswim predators.

Details of Mandarinfish coloration. Photo Credit: Luc Viatour
The mandarinfish has a very distinctive coloration that is unmatched in other fish. Its body coloring includes vibrant colors and variations of green, yellow, orange, brown and blue (Goda, M., R. Fujiyoshi, M. Sugimoto, and R. Fujii 2013).  They are one of two species that have a rare blue colorization due to light-reflecting cells and blue pigments (Preuss 2009). Because of its bright colors and intricate patterns, the mandarinfish is sometimes called “the psychedelic fish” (Aquatic Community 2008). It features wavy patterns and lines of color which are not found as vibrantly in other fish species. These colors help to camouflage the fish in the colorful coral reefs. It is also an indication of their toxic features, warning other fish not to prey on them (Aquatic Community 2008). A small number of individuals have a rare reddish ground coloration (Fish Base 2011). In addition, the colors of the S. splendidus play a part in mating as they flash their colors during dances to attract a mate (Preuss 2009). To learn more about the mating of mandarinfish more information can be found here.

Mandarinfish uses its fins to walk over coral. Source: Childs 2008Most mandarinfish are under six centimeters, with the largest length ever recorded a rare seven centimeters which was found in the East Indies (Fish Base 2011). The fish has a large depressed head (Aquatic Community 2008) and has four dorsal spines, with no anal spines (Fish Base 2011). In males the first dorsal spine is elongated making them larger in size (Patel 2006). Males overall are larger than females and have a bigger dorsal fin to attract mates (Rasotto, M. B., Y. Sadovy De Mitcheson, and G. Mitcheson 2010). S. splendidus use gills to breathe oxygen in water. They have a variety of different fins including dorsal, ventral, caudal, and pectoral which are used for different movement. Mandarinfish quickly pulse their fins while swimming, much like the hovering motions of a hummingbird, though generally they are slow swimmers (Preuss 2009). S. splendidus also have larger, fan-like, pelvic fins which they use to walk along the bottom of the ocean, as seen in the photo above (Patel 2006).

Click here to learn more about the how the mandarinfish reproduces.

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