Half & Half Wrasse

Half & Half Wrasse: The Giant Thicklip

The Half & Half Wrasse (Hemigymnus melapterus), also commonly known as the Blackedge Thicklip, Blackeye Thicklip, or Banner Wrasse, is an impressive and challenging species known for its remarkable size and specialized feeding habits. As its common name suggests, the juvenile form features a striking bicolored pattern: the anterior (front) half of the body is a light, silvery-white or pale green, sharply transitioning to a velvety black on the posterior (rear) half. This dramatic coloration fades as the fish matures, becoming an overall deep green with pale blue and pink markings on its distinctively thick lips and head.

Hailing from the Indo-Pacific, this wrasse is one of the largest species available in the trade, capable of reaching a massive 15 to 20 inches (38-50 cm)—though wild specimens can grow up to 3 feet (90 cm). Due to its ultimate size and extremely high bioload, the Half & Half Wrasse should only be considered by expert aquarists with aquariums of 250 gallons or more. In fact, many recommend this species only for public display tanks due to its demanding space requirements.

This species is highly active and requires a significant amount of open swimming area, as well as a deep, fine-grained sand bed (4-6 inches minimum) for burrowing at night or when startled. Like all wrasses, it is a notorious jumper, so a secure, tight-fitting lid is non-negotiable.

Diet & Compatibility:

• Diet: The Half & Half Wrasse is a dedicated Carnivore. It uses its thick lips and powerful mouth to root and sift through the sand, consuming small benthic invertebrates. In the aquarium, it requires a constant supply of diverse, meaty foods, including chopped clam, mussel, marine shrimp, krill, and commercial frozen preparations. Juveniles often require multiple small feedings (4+ times) per day to sustain their high metabolism. Adults may be very difficult to acclimate to prepared foods and may require live options like grass shrimp to thrive.
• Foraging Behavior: Its active sand-sifting will keep the substrate constantly stirred, which can keep detritus from settling but may also cloud the water, demanding exceptional filtration. The fish is also known to pick up and move small rocks and rubble while hunting.
• Reef Compatibility: It is NOT Reef Safe. While generally peaceful towards larger fish, the Half & Half Wrasse poses a direct threat to the entire cleanup crew and small ornamental invertebrates, including crabs, shrimp, snails, and small fan worms. It is an exclusively Fish Only With Live Rock (FOWLR) candidate.
• Temperament: It is Peaceful to Semi-Aggressive. It is generally non-aggressive toward larger fish, but its sheer size and constant foraging activity can be disruptive. It should be housed with robust, active fish that are too large to be considered prey. It is best kept as the only member of its species in the aquarium.

Quick Facts

• Scientific Name: Hemigymnus melapterus
• Primary Common Name: Half & Half Wrasse
• Other Common Names: Blackedge Thicklip, Blackeye Thicklip, Banner Wrasse
• Origin: Indo-Pacific (Widespread)
• Max Size: 15-20 inches (38-50 cm) in home aquaria
• Temperament: Peaceful to Semi-Aggressive (Highly Active Sand-Sifter)
• Diet: Carnivore (Must be fed frequently)
• Minimum Tank Size: 250+ Gallons (Expert Only)
• Reef Compatibility: No (Will eat invertebrates)