I loved watching these guys. These are the only fish who exist naturally in Death Valley because of the high salt content of the water. They only grow to be 2.5 inches long and only live 6 to 9 months.
They are named pupfish because their mating habits look like puppies at play. During mating the males become blue and defend their territory (as seen in the video) by chasing away all other males and females not ready to spawn.