In this Nevada wildlife refuge area, discover a mysterious geothermal pool that houses the world's rarest fish and extends ...

In rare video footage, a male whale shark has been spotted biting at his female partner during courtship. Before now, we knew very little about the secret sex lives of the world's largest fish ...

While pursuing elusive fish species in each region, it's natural to ask: which of them is the rarest in the game? One may look at the Megalodon and its variants from the Ancient Isle to answer ...

The "rare desert fish" is a "small, moderately chubby fish that feasts on a variety of native food sources and has a unique and distinctly red coloration on the underside when in breeding ...

The Devils Hole pupfish is one of the rarest fish in the world, and the underwater cavern is its only natural habitat on the planet. U.S. Fish and Wildlife Service photo by Olin Feuerbacher It ...