Weather and other factors may play roles in why mysterious changes in color, sometimes overnight, occur on oceans, rivers and other waterways.
A Chinese river changed colors overnight in mid-July, prompting a government investigation into why the river in Wenzhou turned blood red.
Government officials said there was no sign of environmental pollution from nearby factories, the Voice of America reported.
However, they didn't rule out environmental pollution as the reason for the sudden color change, according to the China News website.
It wasn't the first time a Chinese river mysteriously turned red.
Illegal dumping caused the Yangtze River in Chongquing to turn red in 2012, the Associated Press reported.
Heavy rains can also cause rivers and streams to change color, AccuWeather Senior Meteorologist Dan Pydynowski said.
"It would lead to runoff of sediment, which would be more of a reddish brown color," Pydynowski said.
Increased water temperatures also play a role in developing algae blooms that can cause water to turn brown or red.
Florida officials have been monitoring an area about 80 miles long and 50 miles wide in the northeastern part of the Gulf of Mexico where red tide has been reported.
Thousands of dead fish including various snapper and grouper species, crabs, flounder, bull sharks, bait-fish, eel, sea snakes and octopus have died as a result, the Florida Fish and Wildlife Conservation Commission said on its website.