''Pomacanthus navarchus'', the blue-girdled angelfish or majestic angelfish, is a marine angelfish from the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region. It occasionally makes its way into the aquarium trade. ''P. navarchus'' is one of the smallest of the larger

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of angelfish. It grows to a maximum length of , but is usually much smaller than this, and can live to be up to 21 years old. Younger fish stay closer to the shallows, but the more mature fish can be found up to deep. Majestic angelfish eat mainly sponges and

tunicate Tunicates are marine invertebrates belonging to the subphylum Tunicata ( ). This grouping is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ...

Juvenile fish Fish go through various life stages between fertilization and adulthood. The life of fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac which ...

are mostly blue in color with white stripes. As they mature, they take on a yellow coloration on the flanks, dorsal fin, and tail.

Description

The body of this fish is laterally flattened. Adult fish have three main colored sections; the anterior section in front of the eyes and the front part of the body is lemon yellow; the central section is funnel-shaped and is deep blue, and the posterior section is reticulated in bright yellow and blue. The sections are separated by pale blue bands edged with black. The mouth and lips are blue as are the rays of the pectoral and anal fins, while the dorsal and caudal fins are yellow, edged with pale blue. There is a long spine on the gill cover which is used in defence. Juvenile fish are dark blue with slightly curved, white lateral stripes. The change from the juvenile to the adult coloring takes place quite abruptly, with little intermediate coloring.

Distribution and habitat

''Pomacanthus navarchus'' is native to the tropical Indo-Pacific region, its range extending from Indonesia and the Philippines to northern and eastern Australia and Micronesia. It can be found at depths down to about on outer reef slopes, channels and lagoons in coral-rich habitats.

Ecology

''Pomacanthus navarchus'' is territorial and is generally found alone, but occasionally in pairs or small groups. It inhabits the

demersal zone The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer o ...

, feeding on sponges, algae,

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

and small invertebrates. It is a

protogynous hermaphrodite Sequential hermaphroditism (called dichogamy in botany) is one of the two types of hermaphroditism, the other type being simultaneous hermaphroditism. It occurs when the organism's sex changes at some point in its life. A sequential hermaphrodite ...

, starting adult life as a female and later becoming a male.

References

External links

* {{Taxonbar, from=Q670614 navarchus Fish of Palau Fish described in 1831 Taxa named by Frédéric Cuvier