You know that shark in Houston floodwater photo? It's totally fake.

There are many reasons to avoid floodwater whenever possible, but residents of Houston struggling under Tropical Storm Harvey's unprecedented downpour needn't fear a shark.

A photo of a shark supposedly swimming through Houston's flooded streets went viral on Monday ... but the photo's fake. 

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The shark in this photo isn't native to waters anywhere near the United States, but was originally photographed watching a kayaker in South Africa. 

Published in a 2005 issue of Africa Geographic, conservation photographer Thomas Peschak snapped the original (and stunning) image while working on a book about great white sharks.

Here's how it happened, according to Peschak:

The shot is iconic, and the shark in it has repeatedly found new digital life. It's popped up in edited photographs that show the shark swimming through flooded streets in various cities for years, from New Jersey to Puerto Rico. 

Peschak himself has written about friends sending him emails about pictures of the shark he photographed, except now photoshopped into some other part of the globe. 

On Aug. 21, 2011, as Hurricane Irene blew through Puerto Rico, Peschak says the shark appeared in an edited photo swimming through a Puerto Rican street. Three days later, it wound up on a news site. The next year, his shark made an appearance swimming through the streets of New Jersey during Hurricane Sandy. 

"I always look forward to receiving emails from friends and family who have spotted the same white shark in a different context," Peschak wrote on his website. "While I will probably never become a legend in my own right, at least my white shark is well on her way."

Sharks shouldn't make the list of things Houston residents are concerned about, but several residents have spotted alligators around as the flooding continues. 

That said, fake photos of alligators are out there, too.

The above photo, for example, has been making some rounds on social media, and while it was taken in Houston, the photo is from April. 

The National Weather Service didn't mention alligators in an earlier "hurricane safety" tweet, but it did say to avoid floodwater "as it may be electrically charged from underground or downed power lines and may hide dangerous debris or places where the ground is washed away."

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