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Snorkeling the tropical reef: How to identify the Sergeant major fish

If you love to snorkeling the Florida Keys, the Bahamas, or other Caribbean destinations, you've probably already made the acquaintance of today's featured guest. These fish are in fact some of the most common on the tropical reef, and they're easy to identify once you learn their name and understand how their name is tied to their appearance. Since I think it makes any tropical island getaway more fun to (a) explore under the sea by snorkeling and (b) know what you're seeing, we've started posting about the tropical reef in our "Amazing Island Nature" posts. (We also post on land- and air- based nature, too, particularly about seabirds and tropical flowers.) It's been a while since our last nature article, so now the Island Runaways are back with 5 fishy facts about...the Sergeant major fish!

sergeant major fish

(A Sergeant major fish above a school of grunts on Pickles Reef, Key Largo. Photo by Matt Kiefer, Flickr.)

By the way, as I've been collecting our five facts, I've takeen out a slim paperback book called Florida Keys Reef Life which I just bought on this past trip to Islamorada. This handy volume is by Idaz Greenberg, and comes from Seahawk Press, the same company that produces those excellent (and waterproof) "fish cards" that help you learn to identify fish in the Keys and the Caribbean.

Seahawk Press

(My new book on Florida Keys Reef Life. Photo by Laura Albritton.)

Fact ONE: The Sergeant major gets its name from the five black stripes or "bars" that run vertically down each side. You'll note that along with the black stripes, this fish also has distinctive coloring. So, as you're snorkeling over some corals, simply remember it's the only sea creature with a military rank!

Fact TWO: While its common name is Sergeant major, the fish has other names you may have heard before, including damselfish and pilotfish.

Snorkeling the Florida Keys

(Sergeant major off the island of Bermuda. Photo by Brian Gratwicke, Flickr.)

FACT THREE: Sergeant majors are known as aggressive, even bossy fish. Males often turn a blue color during spawning or when they are guarding their eggs. They will guard over the eggs until they hatch.

fish guide

(This illustration shows both yellow and blue coloration. Photo by Laura Albritton.)

FACT four: While the Sergeant major is most abundant in the Caribbean Sea, it can also be found as far north in the United States as Rhode Island, and to the east off Cape Verde and the tropical waters off western Africa.

FACT five: These aren't exactly enormous creatures. The average size of an adult is only 5 inches, although they can grow up to a maximum of 9 inches long. But their size seems to make no difference in terms of their bossy attitudes!

Fortunately, sergeant majors aren't endangered, which is for once some good news! They seem like hardy survivors, and you can spot them flitting around rocks and corals, even just off-shore. In fact, this past weekend, I filmed some of them doing their thing off Virginia Key in Miami. You can see the Sergeant majors in action in this video:

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