Psychedelic frogfish

Lore & Background

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 fish has been known to reach a length of 15 centimetres. Its skin is flabby and fleshy, like other frogfishes, and as a member of the order Lophiiformes, it has no scales. The skin covers the dorsal and ventral fins, aiding in camouflage, and may be covered in protective mucus. The coloring is a pattern of yellowish brown or peach colored stripes covering the entire fish, including its fins, except for the hidden skin exposed when the lips are stretched forward, which is pale. At the margins, the skin can appear 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. The fingerprint pattern is unique to each individual, allowing researchers to track multiple fish in the wild.

The face is flattened; the cheeks and chin are extended laterally, much like the sides of a collapsible paper orb. The fish can expand its head and extend its mouth forward, periodically yawning. It has been positively identified only at Ambon Island, Indonesia, found in coral rubble in water 5 to 7 metres deep, about 20 metres from the shoreline. The fish moves by walking on its pectoral fins and using jet propulsion, taking on a ball shape and behaving like a bouncing beach ball. Its diet likely consists of shrimp and small fish. It is presumed to block off tight crevices in rocks and coral, wriggling into holes for up to two minutes. Its skin may be covered with protective mucus that aids in protecting it from scratches, though this may also be an artifact of divers causing a fright response.

The psychedelic frogfish is relatively defenseless, but hiding in tight passages makes it unlikely that any fish capable of swallowing it will be able to reach it. The combination of camouflage and tight cavities makes it virtually impossible to find without overturning rocks and coral. The purpose of the frilled cheeks and chin is unknown, though Pietsch, Arnold, and Hall hypothesize they serve the same function as cat whiskers—to detect movement of potential predators. The ball-like shape when swimming may be a form of camouflage, making the fish look like debris bouncing along the reef.

Reader's Guide

The psychedelic frogfish is significant for its unusual discovery history and distinctive traits. In June 1992, a shipment of assorted fishes from Bali, Indonesia, to the Dallas Aquarium revealed two curious-looking anglerfish that became known as the 'paisley anglers'. They died that same month, were preserved, and misidentified as cryptic anglerfish (Histiophryne cryptacanthus). Their colors faded to solid white, and they were shelved until rediscovery in 2008. The species was first photographed in the wild in January 2008 by Buck Randolph, Fitrie Randolph, and Toby Fadirsyair of Maluku Divers in Ambon, Indonesia, quickly making headlines and being named one of the top 10 species discovered in 2009 by the International Institute for Species Exploration. Researchers debated whether it deserved its own genus or even belonged in the family Antennariidae, but DNA tests proved it belonged in the genus Histiophryne. Ichthyologists Pietsch, Arnold, and Hall collected a holotype on April 2, 2008, and discovered that when fixed in formalin and preserved in ethanol, the fish shrank 23% and hardened, with colors fading to white—consistent with the 1992 specimens. The stripes could still be seen under a dissecting microscope. According to Andy Shorten, co-owner of Maluku Divers, 'Seeking out these fish is probably going to be like the Holy Grail of divers for a while.'

Did You Know?

• The psychedelic frogfish's fingerprint pattern is unique to each individual, like zebra stripes or humpback whale spots.
• It moves by walking on its pectoral fins and shooting water through its gills, taking on a bouncing beach ball shape.
• A female laid a cluster of about 220 eggs, which the female wrapped in its caudal, dorsal, and anal fins.
• Two specimens from 1992 were misidentified as cryptic anglerfish and shelved until rediscovery in 2008.