Fish
Fanfin Anglerfish
Caulophryne jordani · also called fanfin seadevil
Trailing extraordinarily long, thin, filament-covered fin rays through the water like a living sensory net, a fanfin anglerfish detects the faintest ripple of nearby movement in total darkness, one of the deep sea’s most delicately built and rarely seen predators.
Overview
The fanfin anglerfish, Caulophryne jordani, is a fragile, gelatinous deep-sea anglerfish native to deep ocean habitat recorded across every major ocean basin. Its extraordinary filament-covered fin rays, extreme physical delicacy, and permanently fused males make it one of the more sensorially specialised anglerfish species found anywhere in the deep sea.
Sensing prey without ever seeing it
Rather than relying only on its glowing lure, the fanfin anglerfish extends an array of extremely long, filament-covered fin rays into the surrounding water, effectively turning much of its body into a highly sensitive net for detecting movement no eye could ever spot in total darkness.
Status
Least Concern, though population trends remain largely unknown given the difficulty of surveying deep ocean habitat.
Fanfin Anglerfish: common questions
What are the long, thin structures trailing from the fanfin anglerfish?
This species has extremely long, thin fin rays covered in fine filaments, thought to function as a highly sensitive sensory array for detecting the faintest vibrations of nearby prey in the total darkness of the deep sea.
Do male fanfin anglerfish fuse to females?
Yes, like some other deep-sea anglerfish, males of this species permanently fuse to a female's body, losing their independent organs and becoming a living, attached sperm supply for the rest of their lives.
Why is the fanfin anglerfish rarely seen in good condition?
This species is rarely collected intact, since its extremely fragile fin rays and gelatinous body are easily damaged during capture from such extreme depth, making well-preserved specimens uncommon.
How does the fanfin anglerfish attract prey?
Females of this species carry a modified fin spine tipped with a light-producing organ, used to draw prey close in the darkness of the deep sea, in addition to sensing nearby movement with its long, filament-covered fin rays.