Red fins, blue eyes, can't lose

When there's one single population of a species left in the world, what do you do? Do you let it go extinct? Or do you do everything you can to save it?  

In central Queensland, a collective effort is bringing one teeny, tiny fish back from the brink of extinction: the Red-finned Blue-eye. 

In this episode, we take you to its home, where water, deep in the mantle of the earth below, has travelled up to the surface of an arid, inland environment and given rise to what some scientists have called the 'most significant natural springs for global biodiversity in the Great Artesian Basin.'  

So, how did the fish come to be here in the first place? And what's being done to save it?