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Breeding Mandarins
SPLENDOR IN THE GLASS
Article and Photos by Matthew L. Wittenrich
I was 12 when I set up my first marine aquarium. Determined to fill it with bold and beautiful colors from around the world, I was drawn to a fish with fluorescent lines, swirls of green and blue, and bright pectoral fins undulating against an orange body. A long dorsal fin flashed, winning me over. I purchased my first Green Mandarin, Synchiropus splendidus.
Within days, the object of my fascination showed signs of stress. It hunted tirelessly for prey on the captive reef. Days passed, then weeks, as the Green Mandarin grew ever more emaciated. My splendid fish slowly wasted away and finally died. Thus began my 14-year boycott of mandarins.
Only when someone asked why mandarins weren't included in my book, The Complete Illustrated Breeder’s Guide to Marine Aquarium Fishes, did I realize how long it had been. Today mandarins are nearing the top of my favorite fish list.
NEW HOPE FOR A FAVORITE SPECIES
Mandarins are among the most beautiful marine fishes in the aquarium trade. Their bold colors and contrasting patterns seem to come alive on the reefscape. Sadly, the Green Mandarin and its congener, the Spotted Mandarin, S. picturatus, exhibit one of the trade's highest mortality rates. Tiny mouths and a preference for live crustaceans make them a challenge to feed in captivity.
Until recently, most died from starvation within months. Today, dedicated hobbyists teach their mandarins to accept frozen and pellet foods, thus proving that with a bit of patience, they are no longer for experts only.
BREEDING BASICS
The difficulty of rearing mandarins, coupled with my concern about wild capture methods, led me to experiment with new techniques and foods. Green Mandarins gather nightly where females mate with the largest males. Collectors target and spear the largest mandarins and the mortality risk is high. Females are left to mate with smaller, inexperienced males, exposing them to predation and putting their conservation status in question.
A healthy brood stock is essential for breeding mandarins. Choose alert, active, and full-bodied specimens. Wild mandarins are starved during transit to retailers and often arrive emaciated. Even with a supply of live food, it's difficult to save an emaciated mandarin. Although they pick at the substrate and seem alert, most will perish.
Many aquarists report endless quarrels among captive pairs. Aggression usually arises from insufficient food supplies and poor overall condition. It subsides with proper feeding techniques.
CARE AND FEEDING
Mandarin larvae, among the ocean's smallest, are capable hunters. Juveniles devour newly hatched Artemia and microfauna, but the key to their survival is getting them to recognize still matter as food.
By day 50, when they begin to resemble adults, mandarins forage almost constantly and require high-protein foods to thrive in captivity. There are two ways to satisfy this requirement. One is in a mature aquarium with a lot of live rock, but even with refugium-supported copepod growth, mandarins still die of starvation. It's better to start with a live-food diet, then wean them to accept frozen brine and mysis shrimp. After that, the rest is easy.
Although unnecessary to trigger spawning, I use two bulbs, bright and actinic, to mimic dusk and dawn so I can view the nightly spawning events. The sight of a pair in a spawning ascent, shedding gametes, is amazing.
THE NEXT GENERATION
The red morph is a desirable natural variation but little is known about it. The future may hold designer mandarins with enhanced patterns and colors. Our achievements as culturists will help determine future generations.
Captive-raised mandarins are ambassadors for their species. Nothing is as rewarding for me as watching visitors excited about seeing the first captive-raised mandarins ever to be on public display.
Image: Green Mandarin juveniles bred by the author. Read the full story in CORAL, January/February 2009.
