Latin name

Cyclichthys orbicularis

Other name

Cyclichthys orbicularis

Identification

The Birdbeak Burrfish has a rounded body covered with short spines, each with a triangular base. All spines on the top of the head have three subcutaneous roots. The mouth is small. 

Features of fish fins

The dorsal fin has 11-13 soft rays and the anal fin has 10-12 soft rays. 

Fish colouring

Coloration is pale brown on top, white underneath; round brown spots are scattered over the body, especially near the tail. Fins translucent. Pelagic fry are covered with black spots.

Distribution

Widespread in tropical waters of the Indo-West Pacific from the Red Sea to the Philippines. Also common in the waters around Cape Town, South Africa. 

Habitat

Tropical marine species. Usually found on coastal shelves, in the water column from the surface to a depth of about 150 meters. Prefers areas where the seafloor is covered with soft sediments such as sand, but can be found over reefs.

Size

A medium sized fish, it can reach lengths of up to 30 cm. 

Behavior

This species can inflate itself by swallowing water. In this state it has a spherical shape and its spines are raised. Once inflated, it does not swim well. Nocturnal species. Active at night and dusk.

Food and feeding habits

Birdbeak burrfishes are thought to feed on hard-shelled invertebrates.

Reproduction

Observations of a pair of captive fish showed that two individuals would lay together on the bottom sediment the day before spawning and produce two clutches of fertilized eggs. The embryo and rudimentary eyes formed within a day of spawning and the larvae hatched the next day. They averaged 3.5 mm in length. At this stage, the mouth and anus were still closed, and the head and torso were covered by a vestibular dermal sac. The webbed pectoral fins were clearly visible. Melanophores and xanthophores were scattered throughout the body and the eyes were unpigmented. The eyes became pigmented and the mouth opened within 19 hours of hatching. Two days after hatching, the dorsal and anal fins were separated. Five days later, soft rays became visible in the pectoral fins and the juveniles reached a length of 3.7 mm. One week later, soft rays became visible in the dorsal and anal fins. Seventeen days after hatching, 21 pectoral, 12 dorsal and 10 anal soft rays were present and spines began to appear. These grew to a length of 7.6 mm and became rigid by day 39 after hatching, although they continued to grow and develop thereafter. At this age the fish were 20.8 mm long.

Fishing

It is a commercial fishery. Birdbeak burrfish are sometimes caught in large numbers in trawls. 

Relationship with a person

Harmless.