Fish are strange creatures. Most of them are funny looking, some are downright ugly and a rare few are beautiful (I’m thinking of tropical fish shimmering with bright colours on a reef). But still, I think very few people would classify fish as ‘cute’ or ‘pretty’. And few fish are uglier than the subject of today’s post, the leafvent anglerfish.
Most anglerfish are fairly ugly and scary (think of that scene in Finding Nemo), but the leafvent has an extra level of weirdness. It is a largely translucent fish, making it look even stranger. Here’s a picture:
Leafvents are, like all anglerfishes, deep sea creatures. They swim slowly in the darkness, using a bioluminescent lure to attract smaller fish which it then gobbles up. This deep sea lifestyle is the reason for the leafvent anglerfish’s lack of colour; there isn’t much need for pigmentation when the world you live in receives no source of light.
The leafvent angler has another important adaptation to deep sea life, involving reproduction. Being very slow-moving fish, leafvents have no easy time finding mates in a vast world of cold darkness. So when these lonely animals do find a mate, they make the most of it.
Female anglerfish are much, much bigger than the males. When a male finally encounters a female, he bites her and holds on with his teeth. Eventually, the two animals fuse, and the male transfers sperm into the female. But after this mating, the male doesn’t let go. Instead, he stays attached, and does so for the rest of his life. The male loses his eyes, jaw, teeth and fins, and is basically a pair of testes sticking off of the female, supplying her with a constant supply of sperm. If that isn’t an odd way to live your life, I don’t know what is.
The female’s blood has more than enough nutrients to keep this modified sex organ alive, and it’s not uncommon to see a leafvent female with more than one male attached. Though it seems like an unhappy fate for the males, it is a useful way to ensure the female always has sperm, when finding mates is such a chancy affair.
I’ve never seen a fish quite so ugly as the leafvent anglerfish. Even things like the blobfish have a certain twisted charm to their looks. Maybe her poor looks are the reason that males lose their eyes once attached to her! In any case, ugly or not these fish are certainly interesting, and I’ve had a fine time blogging about them.