[DominikGiggs]

On December 29, 2010 waters of this river in Goldstream Park, Canada, turned neon green. According to the local Environment Ministry, there was a chemical reaction in the water known as “fluorescein”. They believed that somebody dumped fluorescein in the Goldstream River to make a holiday season joke, but that substance wasn’t toxic and fish along with the habitat weren’t affected.

[collaredgirl65]

It's kind of cool looking and thankfully it won't hurt the wildlife.

[sprchrgdtrky]

[aintthatathing]

Im calling fake.

[St. Geno]

I wanna swim in it

[chris]

That's bad ass!!!

[vnathan]

Can I glow green if I drink it?

[gatagato]

Despite it's safe for environment, it's not fully safe for humans:

Topical, oral, and intravenous use of fluorescein can cause adverse reactions, including nausea, vomiting, hives, acute hypotension, anaphylaxis and related anaphylactoid reaction, causing cardiac arrest and sudden death due to anaphylactic shock.

But since they had to use a small amount of it, likely nothing bad will happen.
Found a video
<object width="640" height="385"><param name="movie" value="http://www.youtube.com/v/aO_-gwiteFE?fs=1&amp;hl=it_IT"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/aO_-gwiteFE?fs=1&amp;hl=it_IT" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="640" height="385"></embed></object>

A fountain in Langford, B.C. also ran green around the same time as the river: you can see it here (@ 1:51) it shows also the tests results.
<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/NaNHo6QEeZc?fs=1&amp;hl=it_IT"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/NaNHo6QEeZc?fs=1&amp;hl=it_IT" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
Definately a funny but also stupid prank.
Thanks for sharing

[gatagato]

Sorry: i wrote 1:51 but actually it shows @ 0:42, lol

[Faline]

Proper cool!