The female is about the size of a football and its body is covered in long antennae, used to detect the movements of any prey nearby. The male is about a tenth her size - the size of a ping pong ball. He forms a parasitic relation with the female, attaching himself to her flesh, ultimately sharing in her blood circulation and becoming a dependable source of semen. It is thought that the extremely rare meeting of males and females would lead to such an arrangement. The Hairy angler has an expanding stomach so that it is capable of eating other fish bigger than itself — due to the scarcity of passing food.
Science: a look inside the belly of the hairy angler | Financial Times
October 25, Museum imaging experts discover that an anglerfish in the collections ate a fish twice its length, giving it an enormous expanded stomach. A rare hairy anglerfish that entered the Museum collections 13 years ago has perplexed researchers with its massive stomach. Little is known about this deep-sea fish and what it eats, but the specimen was so rare scientists didn't want to cut it open to identify its last meal. Now, using micro-CT scanning, a process that takes thousands of X-rays of a sample, researchers have created 3D model of the anglerfish's insides, revealing a fish twice its length folded up in its stomach.
3-D scans reveal deep-sea anglerfish's huge final meal (w/ Video)
Caulophryne polynema is a species of fish in the family Caulophrynidae , the fanfins. It is known commonly as the hairy fanfin. It occurs off the eastern coast of North America across to Africa and as far north as Iceland.