Phallostethus cuulong

Phallostethus cuulong is a species of priapum fish. It was discovered in 2009 and described in 2012. This species is found at depths of 0.5 to 3.5 m (1.6 to 11.5 ft) in tidal canals on the Mekong Delta. This species attains about 25 mm (0.98 in) in standard length and is translucent white. Males have their gonads under the chin – along with a serrated saw and rod for grasping females. The name cuulong is from the Vietnamese name of the river system where they are found, Cửu Long River.