"Discus don't cost thousands of dollars ... The African Basslet is an ultra-rare fish, which means its price can change ...

A coelacanth, known by some as the "dinosaur fish," was spotted in eastern Indonesia in a rare sighting of a species once ...

But perhaps its most famous occupant is one that keeps fighting against all odds: the Devils Hole pupfish, a tiny endangered vertebrate that also happens to be the rarest fish on the planet.