Lunula Triggerfish

Lunula Triggerfish

SCIENTIFIC NAME: Rhinecanthus lunula

Overview
Reef Compatible: NO
Diet: Carnivoree
Temperament: Semi-Aggressive
Origin: Australia

Rhinecanthus lunula, commonly known as the halfmoon picassofish, is a captivating species of balistid triggerfish. It was first described by John E. Randall and Roger C. Steene in 1983. Let’s explore some fascinating details about this remarkable fish:

• Appearance: The halfmoon picassofish exhibits a unique coloration. Adult males are particularly vibrant, with shades of orange and yellow. Their elongated snout and concave dorsal profile make them stand out. Additionally, they have an intriguing feature: a broad, black bar on the caudal peduncle and a curved black line anterior to it, resembling a crescent (hence the name “lunula,” which means crescent in Latin). An orange-yellow band extends from the base of their upper lip across the head to the pectoral base. Their elongate body adds to their distinctive appearance.
• Size: While the standard length of the holotype is 180 mm (7.1 inches), other type specimens range from 45.6 to 218 mm (1.80 to 8.58 inches).
• Distribution: This species has a limited geographic range. Initially known from the Pitcairn Islands to Queensland, Australia, it inhabits the outer areas of coral reefs at depths of 10 meters or deeper. Interestingly, there was a single sighting of R. lunula by scuba divers in Egypt, although other members of the Rhinecanthus genus also exist in Africa.
• Juvenile Differences: Juveniles differ from adults. Their caudal fin is initially rounded and becomes slightly double emarginate as they mature. Juveniles lack certain coloration seen in adults, such as the blackish area on the ventral side and the well-developed black bars below the eyes. However, juveniles have two yellow stripes not present in adults.
• Aquarium Trade: Although rare, the halfmoon picassofish occasionally appears in the aquarium trade due to its hardiness and adaptability.

Next time you encounter this elusive fish, appreciate its crescent-like markings and the mystery it brings to the underwater world!