Blind Cave Fish With no Scales Discovered in Vietnam

A new species of fish (see photo) with no eyes and scales has been discovered on a tiny island in Vietnam's Ha Long Bay.

Biologists from the University of Ljubljana, Slovenia, found the new fish species on Van Gio Island during a survey of Ha Long Bay's biodiversity, led by conservation group Fauna & Flora International (FFI).

The new fish, a type of loach, has been named Draconectes narinosus ( a newly described genus), which is derived from both Greek and Latin terms. "Drakon" is the Greek name for dragon and "nectes" means swimmer.  It refers to Halong which is called "descending dragon," as it is believed that the bay was created by a dragon. "Narinosus" is the Latin term, which means "who has large nostrils."

The inch-long fish is blind and does not have any markings or scales, a  common adaptation for cave-dwelling species that have evolved in darker environments like limestone caves. Ha Long Bay is the largest area of coastal limestone towers in the world.

The fish is limited to freshwater, and cannot live in seawater. It is very likely that the fish is endemic to Van Gio Island, said the researchers. They are yet to find if there are any other related species belonging to the new genus Draconectes narinosus on islands located in nearby regions.

The fish has managed to evolve on the small Van Gio Island which has a maximum width of just about 1,300 feet (400 meters). The freshwater in the cave where the fish was found is just 650 feet (200 m) from the sea and at about sea level. It is sensitive to rainfall, climate change and human activities.

The findings of the study are described in the journal Revue suisse de Zoologie.