When a night diver dipped into the waters off Komodo island, Indonesia, he saw what looked like a living piece of algae slither towards him. It was a predator in disguise: a marine file snake.
“One of my favourite features of the marine file snake is its unique camouflage,” said underwater videographer John Roney in a post on Instagram in 2025. "Its rough skin traps algae, giving it a green, mottled appearance that blends perfectly with mangroves and seagrass.”
Although marine file snakes aren’t a true sea snake, they are fully aquatic.
These serpents are so slow-moving that algae settles on their skin, providing them with a unique form of camouflage, said Roney: “This coating forms because the snake spends long periods motionless, waiting to ambush passing fish.”
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Image and video credit: John Roney | @roneydives
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