The mandarinfish is a little fish, only about 2 inches long. But it makes up for its small size with some “wow” colors—vibrant blues, greens, yellows and oranges. This patterned rainbow has a special meaning for predators: Watch out! Mandarinfish can secrete toxic mucus, a not-so-tasty meal.
Mandarinfish are popular in the home aquarium trade, although they are very hard to keep. It is believed that their populations in the western Pacific Ocean are stable.