One of my favorite reef-dwelling fish is Synchiropus splendidus–common name, Mandarin Dragonet.
Although most reefkeeping sites consider the mandarin dragonet one of the harder aquatic specimens to keep (and they’re not wrong), in the right environment, mandarins flourish, and add a lovely, peaceful patch of color to a reef.
Curiously, the only two species of vertebrates that have blue coloring because of cellular pigmentation are both dragonets: the Blue Mandarin and the Psychedelic Mandarin. (All other blue creatures derive their coloring from light-wave interference caused by purine crystals in their cells, as opposed to true-blue pigmentation.)
In the wild, mandarin dragonets feed exclusively on live copepods, amphipods, and tiny worms that live on coral reefs. Wild mandarins don’t recognize dead things as food, and ignore them, which makes it hard to introduce them to a captive reef. Healthy home aquariums have live populations of copepods and amphipods, but a single mandarin dragonet can strip a sixty gallon reef of these tiny creatures in less than a week–much faster than the populations can reproduce.
Mandarins hunt constantly while awake, roaming the reef with a curious expression while hunting for the tiny crustaceans they crave:
Wherein lies the problem: unless you can train a mandarin dragonet to recognize “dead” foods, or you’re willing to pay $20 a week to buy live “Tigger pods” to repopulate your reef, the mandarin is likely to starve in captivity.
Ironically, a seahorse tank provides the perfect environment for mandarin dragonets to flourish. Despite their vacuous expressions and generally peaceful tendencies, most mandarin dragonets are intelligent fish that can and will learn by observing others. Specifically, they watch the seahorses eat from feeding bowls and figure out that whatever is in the bowls must be good to eat. It typically takes a new mandarin 2-3 days to sample the seahorses’ food, and the minute they taste it, they convert from live to frozen foods. Mine even check the bowls between meals, to see if there’s any left over that got missed:
Mandarins also face trouble when housed with aggressive or fast-swimming fish, because these species can stress and harass the peaceful dragonets as well as outcompeting them for food. Mandarins are slow eaters, and will lose any battle at feeding time.
Our blue mandarin, Flutter, is just over two years old, and chubby (as the species should be) from healthy meals of frozen mysis, supplemented by the copepods and amphipods she hunts between meals. Regular meals of mysis keeps her appetite under control, so she doesn’t decimate the populations, keeping the reef in balance.
Mandarins normally live for several years, so I’m hoping to have her around to enjoy for quite some time to come.
What’s your favorite colorful reef-dwelling fish?