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![You can clearly see the sharp fin just by the tail of this Tang.](http://www.scienceiq.com/Images/FactsImages/tang.jpg)
Besides being beautiful, and well equipped with spines, they also serve an important function in the health of the coral reef ecosystem. This time it’s not their tails, but their diet. These vegetarians’ main food is algae. Algae needs an abundance of two things to thrive. One is oxygen; the other is sunlight, which makes the shallow coral reefs of the tropics a perfect place for algae to proliferate. Left undisturbed, algae would soonblanket the coral in a carpet of green, preventing the tiny coral from breathing and taking in nutrients. Left unremedied, the coral would soon die. To the rescue comes algae-eaters like the Surgeonfish. The mouth of a Surgeonfish is perfectly designed to carefully removing the algae from coral while leaving the coral intact. Their fine row of sharp, small teeth make short work of the algae.
Surgeonfish
come in an amazing assortment of colors, usually with a similar flat,
oval body shape that’s easy to recognize. There are over 70 species of
this fish and they are very common in the shallow coral reefs. One
particular group of Surgeonfish have a strange knob growing out of
their foreheads, making them look like the mythical unicorn. As you
probably can guess, these are called Unicorn Fish. Whether you call
them Unicorns, Surgeonfish or Tangs though, remember that a quick swipe
of their tail and you might need a real surgeon to sew you back up.
These are surely a ‘look but don’t touch’ fish.