About Hypseleotris compressa (Krefft, 1864)
Hypseleotris compressa has an elongated body that reaches a maximum length of 12 cm (4.7 in), with males growing larger than females. This species lacks a lateral line, and has ctenoid scales. Its overall coloration is variable, but the head is typically yellowish-tan to golden-brown, though it may occasionally be dark brown. The abdomen is usually whitish-red. Outside of the breeding season, males can be distinguished by prominent, variably colored bands on their anal and dorsal fins. The caudal fin is dusky, while the pectoral and pelvic fins are colorless. During the breeding season, males’ coloration brightens dramatically to a red-orange shade, and they sometimes appear to glow; males use this bright coloring to attract mates. Individuals of this species can change color quickly when needed. Hypseleotris compressa is mostly distributed across northern and eastern Australia and south-central New Guinea. It has also been recorded in the Torres Strait, near Muralag and Horn Island. It is most commonly found in flowing freshwater rivers and streams, but also occurs in still water and can tolerate salinity equal to that of seawater. It is typically found in the lower reaches of rivers, but can also live further upstream. It swims among aquatic plants and branches, and will sometimes hide among rocks that it uses as shelter.
