The Tama river just outside of Tokyo has earned the name "The Tamazon". The murky waters contain so many tropical fish they now outnumber local species 5-1. South American cat fish, turtles, alligator fish and the deadly piranha are just some of the exotic creatures that have been found.
It is believed over the years that many people have dumped there unwanted tropical fish into the river.
With the onset of global warming and water from sewerage processing plants flowing into the river the temperature in the Tama has been raised enough to provide an ideal breeding environment to the foreign invaders.
Aljazeeras Steve Chao reports from Tokyo. Shot and edited by Matthew Allard on a Canon 1D Mark IV, 5D and 7D. Underwater shots from a GoPro HD Herocam.