Mandarin Dragonet (Synchiropus splendidus)
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ✅ Yes
• Minimum tank size: 75 liters (20 gallons), but ideally 115+ liters (30+ gallons) with a mature refugium
• Adult size: Up to 10 cm (4 inches)
• Diet: Obligate carnivore, primarily feeding on copepods and amphipods
• Be aware of: Difficult to feed in captivity, requiring an established tank with a large population of live copepods; slow eater that may struggle in competitive environments
Appearance and Coloration
The Mandarin Dragonet is one of the most mesmerizing fish in the marine aquarium hobby. Its body is covered in an intricate pattern of iridescent blue, green, orange, and red swirls, resembling an artistically painted canvas. The elongated pectoral and pelvic fins allow it to “walk” along the substrate, further adding to its unique appeal. Males can be distinguished from females by their elongated dorsal fin spine.
Natural Habitat and Behaviour
Native to the Indo-Pacific, particularly shallow coastal reefs and lagoon areas around the Philippines, Indonesia, and Australia, Synchiropus splendidus is typically found among coral rubble and live rock formations. In the wild, these fish graze continuously throughout the day, feeding on small benthic crustaceans like copepods, amphipods, and worms.
Mandarins are peaceful, slow-moving, and highly cryptic, preferring to weave through dense live rock structuresrather than open swimming. They do not compete well for food and can starve in systems that lack an adequate natural food source.
Tank Requirements and Water Parameters
• Minimum Tank Size: 20 gallons (75 liters) for a single fish, 30+ gallons (115+ liters) recommended for a self-sustaining copepod population.
• Water Parameters:
• Temperature: 24°C – 27°C (75°F – 81°F)
• pH: 8.1 – 8.4
• Specific Gravity: 1.020 – 1.025
• Aquascaping:
• Plenty of live rock is essential, as it provides hiding spots and a habitat for copepods.
• Mature tanks with a refugium are highly recommended to sustain their natural diet.
• Lighting: Moderate to low, as they naturally inhabit shaded reef areas.
• Water Movement: Low to moderate; they do not handle strong currents well.
Diet and Feeding
Mandarins are obligate micro-crustacean feeders, meaning they need a constant supply of copepods and amphipods.
• Natural Diet: Benthic micro-crustaceans (copepods, amphipods, small worms).
• Captive Diet:
• Live copepods and amphipods (essential).
• Enriched baby brine shrimp (as a supplement).
• Frozen foods (mysis shrimp, cyclops, fish roe)—only if trained.
• Some individuals can be trained to eat pellets, but this is rare.
Feeding Considerations:
• Mandarins require continuous grazing, unlike other fish that eat in single feedings.
• A refugium is strongly recommended to provide a sustainable food source.
• If the aquarium does not support a large copepod population, regular supplementation with bottled copepods is necessary.
Compatibility and Social Structure
• Temperament:
• Extremely peaceful and non-aggressive, making them excellent for community tanks.
• Males can be aggressive toward other males, so only one male should be kept unless in a very large system.
• Tank Mates:
• Ideal companions include gobies, blennies, clownfish, peaceful wrasses, and other slow-moving species.
• Avoid aggressive feeders like dottybacks, damsels, and large wrasses, as they can outcompete Mandarins for food.
• Reef Compatibility: 100% reef-safe—does not bother corals or invertebrates.
Important Considerations
• Difficult to Keep: Not recommended for beginners due to feeding challenges.
• Require a Mature Tank: Needs an established aquarium with a large, self-sustaining copepod population.
• Avoid Starvation: Many die from starvation due to lack of suitable live food. Regularly monitor body condition for signs of malnutrition (sunken belly, lethargy).
• Pairing: A male-female pair can be kept if introduced together, but two males will likely fight.