An unusual fish caught in southwestern China's Guizhou province earlier this month prompted speculation of a new animal or possible hybrid species, after fishermen shared a video of the specimen online.

The fish has so far had its head compared to both that of a bird and a dolphin by internet spectators, but scientists are dubious of any explanation involving unknown hybrids or cryptid species.

The Ghizhou Urban Newspaper interviewed Yang Xing, a Communist Party committee secretary of the Fisheries Research Institute of Guizhou Academy of Agricultural Sciences, on June 6th. Yang identified the fish as a common grass carp, and said that similarly deformed fish can be found in many parts of the country.

"This phenomenon has been observed during the growth of fish," Yang said. "One of the main causes is the damage of fish eggs during embryonic development; the second is the high density during the fry cultivation, and the lack of oxygen causes the head to become deformed. In fact, it is a grass carp."

According to Yang, the phenomenon is not due to any genetic mutation.

Andrew Cossins, an animal physiologist at the University of Liverpool in the United Kingdom, disagrees with the idea that there is no genetic component.

In an interview with Live Science, Cossins said that he believes the deformity was likely caused by "either a series of genetic mutations, or environmental pollution in the form of waterborne chemical contaminants that could have disrupted the fish's regular cell growth."

China has struggled with environmental issues caused by pollution, and although steps are being taken to combat these problems, a recent "environmental census" performed by China's environment ministry found that sources of pollution have increased by over 50% in the country since 2010.

Cossins cautioned that the cause of the deformity cannot be determined from a photograph, or even the body--and there is no way to say for certain that pollutants were to blame.

The fishermen reportedly released the fish back into the river from which it was caught.

'Bird Fish' Found in China is Likely Deformed Grass Carp, Say Scientists