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Summary: Bar Jack fish identification is easy once you notice their silvery color and blue stripe down its back. Watch this video of a Bar Jack to help you identify them on the reef.
Don Stark is a PADI Open Water Scuba Instructor with more than 20 years of active diving experience. He is a senior diver volunteer at the New England Aquarium in Boston where he helps...read more
"The marine organism we're going to identify now is the Bar Jack. Whether you're snorkeling or scuba diving in the water of the Atlantic and Caribbean, one of the fish you will most likely see is the Bar Jack. Bar Jacks are silvery fish that have that look that one always thinks of when envisioning a generic fish. Bullet shape, tapering to a forked tail. They are silver in color and are distinguished by a bright blue and black border on their back that runs along the dorsal fin and on to the lower tail. They will also darken their colors when feeding, and can often be seen following over the top of a stingray as it hunts the sand bottom, waiting for the ray to scare up a small tasty tidbit that the fast swimming Bar Jack can grab for a quick snack. Bar Jacks will also be commonly seen swimming in schools near dive boats and edges of walls. They are great fish to watch feed on plankton and other small animals as a scuba diver does his or her recommended safety stop at the end of each dive. Their normal diet is small fish, shrimp, and other invertebrates. They are fairly bold and will swim closely by divers either alone, or often times in large schools. They can also be frequently seen hovering over coral structures in a head down posture, as they are being cleaned by small Spanish Hog Fish or other cleaner fish. Bar Jacks generally range in size from eight to fourteen inches, but some individuals may reach up to two feet in length. They are normally found in relatively shallow waters, anywhere from one foot to sixty feet. Juveniles will often be found under floating mats of sargassum weed. That's the Bar Jack."
eHow Article: Bar Jack Identification