The deep sea anglerfish and its bizarre reproduction

By in Animals

In the darkest depths of the ocean where the water is freezing cold, the pressure is enormous and food is scarce lives the angry-looking deep sea anglerfish. This fascinating fish is not only an incredible example of how organisms manage to survive in the most inhospitable environments, it has one of the most bizarre ways of reproducing in the animal kingdom.

Deep sea anglerfish

The ferocious looking deep sea anglerfish has one of the most extreme methods of reproduction

The deep sea anglerfish is one of the deep ocean’s most fascinating residents. Living at the extreme depths between 1.5 and 2.5 km, their most peculiar appearance is a modified fin that acts as a lure, hanging above their huge mouths containing needle-like teeth. The tip of this “fishing rod” on top of their head is bioluminescent (glowing in the dark) because of bacteria living inside it and attracts prey in a similar way like moths to a lightbulb. By wiggling the glowing outgrowth, it lures prey close enough to devour them whole. Because of thin, soft bones and jelly-like skin, these scary looking fish can expand their jaws and stomach to such an extent that they are even able to actually swallow prey up to twice their own size. In the deep sea where food is very scarce, being able to eat large quantities at once is a great adaptation.

Deep sea anglerfish close-up

The scary looking deep sea anglerfish has long needle-like teeth

Despite their ferocious appearance, the deep sea anglerfish is actually pretty small. Females will only reach a length of about 10 centimetres, while male are only a fraction of this and can be more than 10 times smaller. Males of one specific species of are even the world smallest fish, measuring only some 6.2 mm. However, because of the much larger size of females, it is not the smallest species of fish in the world.

Deep sea anglerfish male

Males of the deep sea anglerfish are very very tiny and may only measure some 6mm!

Because individuals are so sparsely populated, finding a mate in the depths of the deep sea is problematic. To still be able to reproduce, the deep sea anglerfish have one of the most bizarre methods of reproduction.

When scientists first discovered these fish, they kept wondering why all the fish they captured where females. However, after some time they noticed small “growths” on the females skin that, upon closer inspection, turned out to be males (see image below). The tiny males actually only live to find a female. Upon encounter, a male bites into her skin after which the tissues of the male and female become completely fused together so that their blood vessels join as one. The male now assured of a life without the need to hunt for food degenerates his eyes and all internal organs except for its testes.

World smallest fish male angler fish

This 46 mm female Photocorynus spiniceps has what looks like a small nub in the middle of her back. Actually, that’s a 6.2 mm long male, the world’s smallest known, sexually mature vertebrate

A female can carry up to six males on her body at a time and is therefore assured of a fresh supply of sperms. She can reproduce at any time or place without worrying about meeting a male in the darkness of the ocean.

It is astonishing that species can evolve to such extremes that males become nothing more than a small lump on the skin of a female to assure her of her own lifetime supply of fresh sperm.

  • goos

    craaaazy! love the websute jolles! xxxx

    • Jolle Jolles

      Thanks goos! Luckily is homo sapiens have a different reproduction strategy don’t you think? ;-) Good to hear from you!

  • Taiyon’s Image

    Very cool and interesting pictures. So pre-historic!!! I guess that was what you was aiming for.

  • Sanne

    Very cool and interesting blog again Jolle! Didn’t know this fish was so scary. Keep up the good work.

    • Jolle Jolles

      Thanks sanne! Great to hear you like it.


    wow! nice info.

  • Jolle Jolles

    Thanks Sveshka!

  • Deep Sea Angler Fish

    Such a crazy fish, almost like a freak of nature!

  • Maria


  • Matt

    A more humorous version of the Angler fish reproduction. This is not a spam link I promise; it’s just an awesomely funny page that is related.

  • Joll

    Thanks for the funny link Matt!

  • mahboobeh

    Hi ,Thank you very much for your information.I’m an ecologist in iran. I injoy it.

    • Jolle Jolles

      Thanks Mahboobeh! Great to hear the information on is useful to you :)

  • Cameron

    Amazing,fantasic,and marvlous

  • mary@Deep sea Anglerfish

    The deep sea anglerfish give me curiosity on how they create that light. Please post more about more interesting sea creatures . But totally your site is good and very informative.

  • Jolle Jolles

    Thanks Mary! I will try and write more articles about the deep in the near future :)

  • http://gmail roxyshore

    cool facts :)
    i need infos about blob fish someone

    • Connor Norng

      it look a lil bit like a blob

      • Jolle W Jolles

        The males look quite blobby indeed!

  • Bella

    Finding Nemo anyone?

  • devon beckman

    thanks i love anglerfish , i wish we could reproduce like they do ! ;)

    • Dr.Phil

      Pretty sure there are plenty of male humans who act more like a parasite then a care giver and merely hang around for the sex

  • gg


  • babyc

    i think this is a good site to go

  • Amberlyn

    Just wanted to day this was really usefull for my school project!

  • Kate

    Proof read your articles, so many grammatical errors. Good info though!

  • peanuthead

    Since I am doing a project on Deep Sea Anglerfish, this article is very helpful. Thanks!

    • Jolle Jolles

      Thanks! Good to hear it is useful :)

  • Bardelot

    Yep, just like my husband…a blood-sucking parasite good for nothing but sex…

    • Alvin Thz

      Your hubby need sex everyday?

  • Pingback: Uncanny Curiosities: Angler Fish - | Uncanny Tales |()

  • Chad

    Hilarious, and very informative!!

  • domonique

    how does anglerfish have babies

  • Zoe

    Do they give live birth or produce eggs?

    • mudfooted

      Hi Zoe, thanks for your question, the deep sea anglerfish produce eggs

  • Pingback: Kala Sungut Gada Mencari Cinta | fish-tarina!()

  • Pingback: There’s a hole in the bottom of the sea | Reader's Digestivum()