European flounder

The European flounder is a flatfish that hugs the seafloor along Europe's coasts, from chilly northern waters down to the warmer Mediterranean. These masters of disguise can change color to match the sandy bottom. They've also hitched rides in ship ballast tanks, popping up unexpectedly in North America.

• Changes skin color to blend with sandy seabeds
• Accidentally traveled to North America in ship ballast water
• Commonly caught by fishermen for food