Pranksters have been blamed for a stunt that saw a Canadian river dyed bright green: A seemingly meaningless prank played in a beauty spot in the Province of British Columbia has caused the Goldstream river to glow luminous green. Fish remained unharmed and uncoloured by the contamination which lasted no more than an hour. The brightly coloured substance in the video posted on YouTube is fluorescein, commony used as a tracer agent in forensics and water studies. The solution was banned in Chicago in 1962 when it was used to dye the Chicago River green to celebrate St. Patrick's Day. (January 12, 2011)