Description

The Dragon Wrasse (Novaculichthys taeniourus), also famously known as the Rockmover Wrasse, is a truly unique and fascinating fish in the marine aquarium hobby. Its common name “Rockmover Wrasse” is incredibly apt, as it’s notorious for its habit of enthusiastically rearranging the aquarium’s aquascape in its search for food.

This species undergoes a dramatic transformation from a delicate-looking juvenile to a robust and often boisterous adult.

Appearance:

• Juvenile: This is where the “Dragon” part of its name often comes from. Juveniles are slender, often reddish-brown to green with white mottling and distinctive long, filamentous extensions on their first two dorsal fin spines, giving them a “cowlick” or “antler” appearance. They also mimic floating seaweed, swaying with the current to avoid predators.
• Adult: The long fin extensions disappear as they mature. Adults develop a more robust, oblong body. Their coloration is typically a dark greenish-brown to mottled grey, with white spots or blotches on each scale, and often intricate brown lines radiating from the eyes. The caudal (tail) fin often has a distinctive white bar at its base.

Adult Size:

• Dragon Wrasses can grow to a significant size, reaching up to 12 inches (30 cm) in captivity. Some sources indicate they can grow slightly larger in the wild.

Natural Habitat and Distribution:

• Found throughout the Indo-Pacific region, including East Africa, Indonesia, Australia (including the Great Barrier Reef), Fiji, and Hawaii.
• Inhabit shallow reef flats, lagoons, and seaward reefs with mixed sand, rubble, and grassy areas. They are active during the day, constantly foraging.

Aquarium Care (Moderate to Advanced Level):

• Minimum Tank Size: Due to their adult size, active nature, and propensity for moving substrate, a minimum of 120 gallons (approximately 450 liters) is generally recommended for a single adult Dragon Wrasse. Many experienced aquarists recommend 180 gallons or more to provide ample swimming and digging space.
• Water Parameters: Maintain stable marine water conditions. They are relatively hardy but benefit from consistency.
  • Temperature: 72-78F (22-26C)
  • Salinity: 1.020-1.025 specific gravity
  • pH: 8.1-8.4
  • Alkalinity (dKH): 8-12 dKH
  • Ammonia and nitrites must be 0 ppm. Nitrates should be kept below 20 ppm.
• Filtration: A robust filtration system, including a good protein skimmer, is essential to handle their bio-load and cope with the stirred substrate.
• Water Flow: Moderate to strong water flow is suitable.
• Substrate: This is CRITICAL. A deep sand bed (at least 3-4 inches or 7-10 cm deep) of fine-grained sand is absolutely essential. They bury themselves in the sand at night for sleep, and when startled or threatened. They will also continuously dig, sift, and move the substrate around in search of food. Avoid coarse or sharp substrates.
• Diet:
  • Carnivorous: In the wild, they are active predators, turning over rocks and sifting through sand to find small crustaceans, mollusks, worms, small fish, and echinoderms (like starfish and urchins).
  • In Captivity: They are generally good eaters and readily accept a variety of meaty frozen foods.
    • Vitamin-enriched mysis shrimp (a staple)
    • Brine shrimp
    • Chopped seafood (clam, squid, silversides, krill)
    • High-quality marine pellets and flakes can be offered as supplements.
  • Feed 2-3 times daily in small amounts to support their active metabolism.
• Temperament:
  • Semi-aggressive to Aggressive: While juveniles may be more peaceful, adults become quite aggressive and territorial. They should generally be kept singly in a tank.
  • They can be housed with other larger, more aggressive, or semi-aggressive fish (e.g., triggerfish, large angels, puffers) that can hold their own.
  • They are generally not compatible with other wrasses unless the tank is exceptionally large.
  • Rock Moving: Be prepared for them to rearrange your aquascape significantly. They will tirelessly move small rocks, shells, and even unmounted corals in their quest for food. Ensure all rockwork is extremely stable and secured to prevent collapses.
• Reef Compatibility: NOT REEF SAFE. This is a crucial point. As they mature, Dragon Wrasses will actively prey on most small invertebrates (shrimp, crabs, snails, smaller starfish, worms) and can disturb or even damage corals by constantly moving them or knocking them over in their digging. They are best suited for fish-only with live rock (FOWLR) aquariums.
• Tank Setup:
  • Provide sturdy live rock structures that are well-secured to the tank bottom or each other (aquarium epoxy is useful here) to prevent collapses from their digging.
  • Ensure ample open swimming space and a large, deep sand bed.
  • A tight-fitting lid is absolutely essential as they are notorious jumpers, especially when startled or new to the tank.
• Acclimation: Slow and careful drip acclimation is crucial.