These beautiful mandarinfish (Synchiropus splendidus) are covered in bright blue, red, yellow and orange waves. What they lack, however, are traditional fish scales. They live in western Pacific tropical coral reef ecosystems and instead of your typical fish scales they are covered in a smelly, thick mucus coating. It's possible that this mucus, which not only smells—but tastes—bad, is used as a deterrent to predators.