Order : Perciformes
Family : APOGONIDAE
Species : Apogon hyalosoma
Maximum Length : 20 cm

There are over 200 species of Cardinalfish in the family Apogonidae, the majority of which are included in the genus Apogon.

The Humpbacked Cardinalfish Apogon hyalosoma is a species of estuarine habitats, particularly mangrove. At low tide small shoals may be spotted congregating  in quiet, shady pools.

Its body shape is robust and rhomboid, with large scales on the flanks. Its forehead is slightly concave and its mouth and eyes are large.

There are two dorsal fins of roughly equal size. The tail and other fins are mainly white to translucent, except for the leading edge of the first dorsal fin which is dark red to blackish. At the based of its tail is a distinctive large, black spot. 

This is a predatory species which feeds on a variety of small prey items.

This species is widely distributed in coastal waters of most countries in Southeast Asia except, perhaps, Burma. It also occurs widely in the western Pacific Ocean, including the coast of Papua New Guinea.

Fig 1 : A small shoal of Humpbacked Cardinalfish in a quiet mangrove pool at low tide. Also in the picture is a  species of mullet.

Fig 2 : This fallen tree provides some shelter at low tide  for shoals of this species.

Figs 3 and 4 : Small groups of the species lie motionless near the water's surface.

All photos at Burau Bay, Langkawi, Peninsular Malaysia.  

References : F3, F4
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