Adults have a narrow line of dark blue along their dorsal fin that curves back at the tail. Its resemblance to the numeral 6 gives the fish one of its descriptive names. You may like Whales ...

Each tag has a unique number and will be attached to the fish near the dorsal fin. Anglers who catch a tagged ... may also be eligible for rewards. Blue tags will be entered into a drawing for ...

For the study, a team from Florida Atlantic University captured six of the groupers from a canal on Florida's Hutchinson Island, and affixed one of the tags alongside the dorsal fin of each fish.