Trumpetfish: Sneaky, Relentless Predators on the Reef

THINK ABOUT THE MOST RELENTLESS HUNTERS ON THE REEF and you probably envision menacing sharks, barracudas and moray eels. But those are mere grandstanders in the predation game. High on the list of sneaky relentless predators would have to be a species of fishes that Caribbean divers encounter so frequently – and that appear so benign – that they’re likely to take them for granted and ignore them. After all, the ever-present trumpetfish (Aulostomus maculatus)

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Balloonfish & Porcupinefish: Big Eyes, Mona Lisa Smile

WHAT’S THE DIFFERENCE BETWEEN BALLOONFISH AND PORCUPINEFISH?  They’re both unobtrusive, usually little guys with an ability to inflate into spiny basketball-shapes when disturbed. It’s a defensive response to threats. And, divers are often confused as to which is which. First of all, when you see picture of them, they’re often inflated like stuffed pincushions. In fact, like this…. But the truth is that recreational divers who are minding their manners are unlikely to see them

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Hamlet Fishes: Chasing the Hamlet Grand Slam

WHO KNEW THAT SPOTTING LITTLE GUYS LIKE BUTTER AND BARRED HAMLET FISHES could be challenging? I’ve thought of them as fairly bland little fishes of modest interest. I’m aware of occasionally seeing vivid blue indigo hamlets (Hypoplectus indigo) in Bonaire and Belize but not the other dozen or so species to be found around the tropical Atlantic/Caribbean. Which sounds fishy considering that Humann and DeLoache’s Reef Fish Identification says barred hamlets (Hypoplectus puella) constitute the most

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Glass or Masked, Gobies We Hardly See You

THESE LITTLE GUYS ARE SO SMALL AND TRANSLUCENT THAT YOU HARDLY NOTICE THEM, but they’re actually pretty common on reefs in the Caribbean. Tiny fishes that swim in swarms of a dozen or so just off the corals, they’re either glass gobies or masked gobies. Both an inch or so in length, the two species are so similar that one source suggests the only way to be sure is to hold them in your hand

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Eels in Seals’ Noses: No One Knows Why

ONE EEL UP A SEAL’S NOSE IS AN EVENT. FOUR EELS IN SEALS’ NOSES IS A FAD. Like teenagers swallowing detergent pods, Hawaiian monk seals seem to be chasing a trend – stuffing eels inside in their nostrils. At least, that appearance baffles staff at the Hawaiian Monk Seal Research Program, an NOAA agency based in Honolulu. Unknown until recently, the researchers have encountered the eels in seal’s noses phenomenon several times in the past

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Bluehead Wrasses – The Great Damselfish Egg-Raid

IF YOU’VE DIVED IN THE TROPICAL ATLANTIC/CARIBBEAN, you’ve almost certainly seen bluehead wrasses. Of course, most of them weren’t blue. The blueheaded members of bluehead wrasse world are terminal-phase males, or supermales. Despite their high visibility, they make up no more than 10 percent of a given bluehead wrasse population. The overwhelming majority of bluehead wrasses are yellow – juveniles or initial-phase adults or something in between. Blueheads (Thalassoma bifasciatum) are among those fish that

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 Fish Buoyancy – How Our Finny Friends Stay Neutral (Unless They Don’t)

ONE THING IS CLEAR – FISH HAVE BETTER BUOYANCY THAN YOU.  And, they don’t have to press any buttons. Many bony fishes have built-in versions of the buoyancy-compensators that divers use to control their position in the water versus changing ambient pressures. In these fishes’ case, it’s an internal gas-filled sac called a swim bladder that automatically works to counteract the ambient pressures applied by the waters surrounding it and keep the fish at neutral

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Bluehead Wrasses on an Egg Raid – An Awesome Video

AS A STUDENT OF LIFE UNDER THE SEA, I’m always curious about behaviors. So when, on a dive, I saw a pack of little yellow initial-phase bluehead wrasses streaking toward a distant point, naturally I followed them. They were almost certainly on an egg raid. Blueheads are notorious for plundering the egg nests of other species of fish, particularly damsels and blennies. BLUE HEADS & YELLOW BODIES To be clear, bluehead wrasses get their name from the

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Fish Hunting Parties

ANIMALS IN THE OCEAN ARE ALWAYS LOOKING FOR FOOD (and trying to avoid being food). Some times it involves more than one animal. On Bonaire, one year, I encountered several instances of group fish hunting. Sort of. There’s a known phenomenon called Nuclear Hunting in which a small eel (like a goldentail moray) and one or more other fishes (like rock hinds) meet up, identify a nearby coral head as a target site and race toward

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Seahorses Are Super-Predators – An Awesome Video

IT MAY BE EXCITING TO FIND SEAHORSES ON DIVES – but watching them is like watching grass grow. They’re inept swimmers, so they rarely swim unless they have to.  But it turns out that seahorses are super-predators, more than 90 percent effective at bagging their prey – mostly tiny shrimp and copepods. WHY SEAHORSES ARE SUPER-PREDATORS – ANATOMY & SPEED One study using high-speed video to record seahorses’ movements found that the seahorse’s curved-body architecture

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