The psychedelic frogfish (Histiophryne psychedelica) is a yellow-brown or peach colored frogfish named for its pink and white stripes arranged in a fingerprint pattern. The fish is from waters near Ambon Island and Bali, Indonesia.
The psychedelic frogfish was first described in 2009 by Pietsch, Arnold, and Hall in the scientific journal Copeia, where they described it as having "a remarkable pigment pattern of white swirling stripes", hence their use of the term psychedelic. The psychedelic frogfish has been known to reach a length of 15 centimetres (5.9 in). The skin of the psychedelic frogfish is flabby and fleshy, like other frogfishes. As a member of the order Lophiiformes, it has no scales. The skin covers the dorsal and ventral fins of the fish, which aid in camouflaging the fish. The skin may be covered in protective mucus.
The psychedelic frogfish is different from many other anglerfishes in that it has a tiny luring appendage on its forehead. It has a relatively flat face, and forward facing eyes with a mouth smaller than that of most anglerfishes.
The coloring of the skin is a pattern of yellowish brown or peach colored stripes. This pattern covers the entire fish, including its fins, except for the hidden skin that is exposed when the lips are stretched forward, which is pale in color. At the margins, the skin can appear to be turquoise, although the exact nature of this coloration is unclear. Unlike some frogfishes, the psychedelic frogfish's color never changes, even if the habitat changes, and its offspring maintain that color as well. The fingerprint pattern, like the stripes on a zebra or the spots on a humpback whale's tail, is unique to each individual. This allows researchers to easily track multiple psychedelic frogfish in the wild and still identify them from any angle.
The face of the psychedelic frogfish is flattened; the cheeks and chin of the fish are extended laterally, much like the sides of a collapsible paper orb. The fish is able to both expand its head and extend its mouth forward, thus expanding the head and giving it a more elongated shape more often seen in large fish. The fish employs this behavior periodically when not feeding, as though yawning.
The psychedelic frogfish has so far been positively identified only at Ambon Island, Indonesia. It has been found in coral rubble, where it may be camouflaged from predators, though the location is primarily considered a 'muck' dive with few corals in the area. The fish have so far been found in locations where the water is 5 to 7 metres (16 to 23 ft) deep, about 20 metres (66 ft) away from the shoreline. Occasionally, the current in these areas is so strong that it makes it nearly impossible for the fish to swim, but usually the current is only mild.
The coloration of the fish may be reminiscent of a number or hermatypic corals such as Symphyllia sinuosa, Leptoseris explanata, Pachyseris rugosa, Platygyra ryukyuensis, Pectinia lactuca, and Caulastrea furcata, all located in the Indo-West Pacific area.
The psychedelic frogfish moves by walking on its pectoral fins over the seafloor, and has been observed using its fins to push off from the sea floor while at the same time shooting water through its gills to propel itself forward via jet propulsion. When doing so, the fish takes on a ball shape, and its behavior takes on that of a bouncing beach ball in the wind. These modes of locomotion are quite common for frogfishes, although rare for other fish.
The fish's diet likely consists of shrimp and small fish. Fish cannot be attracted using the illicium, as this spine is so reduced in size that it is unnoticeable externally.
Instead, the psychedelic frogfish is presumed to strategically block off tight crevices which serve as passages to chambers in rocks and coral. The psychedelic frogfish was reported to wriggle itself very tightly into these holes, pushing with its fins, often for as long as two minutes before making its way inside the hole. Its skin may be covered with a protective mucus that aids in protecting it from scratches. This may also be an artifact of divers causing a fright response, especially when using high-powered strobes on underwater cameras.
