According to CTV, it seems pranksters used a non-toxic substance known as fluorescein to pull off the stunt in British Columbia’s Goldstream River. It’s a substance used in medical procedures, but is non-toxic and essentially harmless. A few wildlife officials aren’t so thrilled however, as they still think the prank might have unforeseen consequences on the local ecosystem. But come on…if they can’t take a joke that requires the use of tax dollars to investigate and clean up the water, then, well…OK maybe they’re right. [CTV via AOL]