Frogfish blend with surroundings, use specialized lure to attract fish
Many animals rely on the ability to camouflage to avoid detection from predators, but in the case of the frogfish, camouflage is used to lure in its prey. The frogfish is one of the most peculiar looking fish in Hawaiian waters, yet it is astonishingly well-suited for the marine environment. Easily mistaken for a rock overgrown with algae or a harmless sponge, frogfish blend in with their surroundings and use a specialized lure to draw in curious fish, only to be consumed in the blink of an eye.
Often called anglerfish, the nine species of frogfish that inhabit Hawaiian waters are relatively small in size. All frogfish in the family of Antenariidae have a first dorsal spine that is used like a fly fishing rod, which it casts back and forth over its enormous mouth. This ambush predator sits on the reef waving its lure until a curious fish gets close enough to become lunch. The reflex of a frogfish is so fast it is measured in milliseconds. With a prognathism mouth, meaning its jaw can protrude outward, frogfish have the incredible ability to consume prey longer than their own body.
Frogfish have unique prehensile pectoral fins. These limb-like fins look like they have an elbow, making it a curious sight to see. Using its pectoral and pelvic fins, it has the ability to hold and stabilize itself on the reef as it waits for an unsuspecting prey. The pectoral fins also allow it to walk (yes, walk!) along the ocean floor, an unusual behavior for a fish. In addition to using its tail fin to swim, frogfish have the unique ability to use jet propulsion. This is achieved by forcefully pushing water through its gill opening to propel itself forward. These gill openings are located behind the “elbow” joint of the pectoral appendage, unlike having gill covers toward the back of the head as many fish do. This may also contribute to the frogfish’s ability to stay hidden.
Frogfish can display a broad range of colors, allowing it to effectively adapt to its surroundings. Some species of frogfish range from bright yellow, red, orange, black or brown. Maui Ocean Center’s aquarists have described certain species of frogfish changing colors in a matter of days or weeks to better match their environment. It’s no wonder they are frequently missed by divers.
The Commerson’s Frogfish (Antennarius commerson) is the most common species seen by divers in Hawaii, and is much larger than other species inhabiting the Hawaiian archipelago. Obtaining a length of up to 15 inches, the Commerson’s Frogfish, like other species of frogfish, is a master of camouflage and disguise. Associated with deeper depths, it is typically found in coral reef environments where abundant sponges are present. They are considered solitary but will occasionally gather during mating season. The Commerson’s Frogfish feeds on fish and shrimp using the same specialized lure on its first dorsal spine.
Look closely on your next dive, maybe you’ll spot an intricate yet astonishing animal like the frogfish.
* Lily Solano is a marine naturalist at Maui Ocean Center. “Ka Mo’olelo Moana,” or “the Ocean Story,” is a monthly column submitted by Maui Ocean Center staff members. The center is open from 9 a.m. to 5 p.m. daily in Maalaea. For more information, call 270-7000.