Saddleback Butterflyfish, Chaetodon ephippium

 As an underwater photographer I love taking pictures of nudibranchs because they are colorful and move very slowly. This makes taking photographs relatively easy. Fish often present much more of a challenge. They swim very fast, and usually away from you. It takes a fast shutter speed and a keen sense of timing to capture moments like this.
  The saddleback butterflyfish, Chaetodon ephippium, is a rare species of butterflyfish to see here in the Hawaiian islands. They usually travel in pairs but this picture is of a loner. I knew I had a chance to get a good picture because this fish was being cleaned by a cleaner wrasse. Fish will usually stick around for that critical extra second when getting cleaned. 
 The other tip is to get the fish sideways but just turned to look at the camera. Having its mouth wide open in this moment was an extra bonus. If you find yourself snorkeling out here in Hawaii, put this fish on your underwater treasure hunt list. Its a beauty.