It’s always exciting when science discovers a new species of plant or animal sharing our planet. Most of these discoveries tend to come from remote rain forests or the deep ocean. What’s really fascinating is to find a new organism that’s been living right under our noses. Such is the story of that gorgeous fish pictured above ("gorgeous" being an objective term, of course).
The first specimen of psychedelic frogfish (Histiophryne psychedelica) was found by divers on the Indonesian island of Ambon. Ambon is one of the "spice islands" and was the headquarters of the infamous Dutch East India Company in the 17th century. Today it’s famous for tourism and as the home of one of the weirdest fish around.
Even those species of frogfish that don’t look like they were dressed in the ’60’s are pretty strange creatures. All of them belong to the larger group of fish known as anglerfish. Anglers have a detached fin ray on top of their heads which serve as bait to attract prey. This flexible rod, known as an illicium, is normally tipped with a fleshy tab at the end. The tab, called an esca, resembles a fish or a worm that will hopefully look enticing enough to attract the attention of a smaller fish. When the prey closes in to investigate, the frogfish snaps its huge mouth open and draws the food in. Psychedelica is no ordinary frogfish, though. As far as I know it’s the only species that lacks this illicium.
Because they are lying-in-wait predators the body plan of a frogfish isn’t exactly built for speed. The body is globular, lumpy and often covered in growths and fleshy tabs to camouflage it among the rocks and corals. The pectoral fins, which normally resemble wings on most fish, work like little hands used to prop the body up while lying on the ocean bottom.
On other fish these pectoral fins are situated just behind the gill openings. Anglers are unique in that the gill openings are found behind the pectoral fins. This is important because it allows the fish to move. Frogfish don’t swim. They move using a combination of fin walking and jet propulsion. And the power for jet propulsion comes from water streaming out of the tubular-shaped gill openings. Frogfish travel across the bottom with slow little steps using their fins, followed by a hopping motion as the little gill jets kick in. They always remind me of those videos of an astronaut on the surface of the moon.
Once again this species deviates from the frogfish norm. Employing the same maneuvers described above, it goes a step farther by taking on a ball shape once "air borne" and bounding across the bottom. One of the divers who first spotted this fish compared it to a beach ball in the wind. Watch one bouncing around in the video below. It really gets going around the halfway point.
Another astonishing feature of Psychedelica is the forward-facing eyes, a trait that is very unusual in fish. Combined with the generally flattened face, this frogfish has similar depth-perception capabilities as mammals do. Little is known so far about its feeding behavior, but since it can’t attract fish like other anglers, it probably simply waits for prey to come close enough to be ambushed. It’s size (about six inches) and body shape is very similar to my local toadfish, also an ambush predator, so I’d guess it feeds in this way.
A while back I posted a diary on a very closely related angler called a sargassumfish.
Fun Fact: The psychedelic frogfish was actually first discovered a few decades ago, but the specimen was misidentified and sat in a jar of formaldehyde for years.
[Update, 9:20pm est]: I just learned that those markings are unique to each fish, like fingerprints, and can be used by researchers to identify individual specimens.
Other diaries in this series can be found here.