The blobfish: A bloated guide to the world's ugliest animal (and what they really look like)

It's the internet's favourite fish, a charmer from the deep with a face that only Mother Earth could love. Yet the blobfish – a fat, lazy bottom-feeder that's relatively new to science – has somehow cast a spell over human beings, who have made memes, soft toys and emojis inspired by it.

It may be hard to forget, but what do we actually know about the blobfish? What's the real reason it looks so glum? And what can it teach us about conservation or the secretive habitat in which it lives?

The first thing to clear up is its name. The term 'blobfish' is used to describe a number of different species as well as the wider fish family known as Psychrolutidae. For most of us, however, the blobfish is a particular species (Psychrolutes microporos), the first specimen of which was found by a research vessel off the coast of New Zealand in 1983.

It was another decade before it was formally described and identified. And even now, there are large gaps in our understanding of this enigmatic sea creature, despite a number of other samples being found in trawler nets.

Despite the unknowns, the blobfish found widespread notoriety after another specimen was photographed in 2003, its gelatinous appearance making it a gift to early internet culture. Droopy, slimy and very easy to anthropomorphise, it was later named the ugliest animal in the world in a poll set up by the Ugly Animal Preservation Society, a conservation group that argues it's not just the cute critters that deserve our protection. The 2007 specimen was nicknamed Mr Blobby.

What is a blobfish?

Before finding fame as an internet meme, the blobfish was a scientific curiosity. A member of the Psychrolutidae family, it is sometimes referred to as a sculpin or (for obvious reasons) fathead. It is a deep-sea fish and its popular appearance is misleading: it only looks like a 1980s dessert when it's brought to the surface.

Why does the blobfish look like that?

Blobfish species live in some of the deepest pockets of the ocean, at depths between 600 and 1,200m. Down there, the pressure can be more than 100 times what the atmospheric pressure you feel right now, and the fish has adapted accordingly. Its body is squishy, with soft bones and very little muscle.

When a blobfish is caught in nets and brought to the surface, decompression can make it expand and cause its skin to relax, distorting its features and giving it that characteristic big nose. And on land or the deck of a boat, its gelatinous tissue doesn't hold its structure, so it collapses into shapeless mass much like a washed-up jellyfish.

"The image everyone knows about is really hideous because it's a dead one," says Simon Watt, the biologist, comedian and science communicator who set up the Ugly Animal Preservation Society. "In the wild, they're not exactly beauty kings or queens but they're not quite so depressed-looking."

It’s the same as if we shoved a human to a depth of 1,200m without any protective gear or breathing apparatus. We would look pretty disgusting too!

What does a blobfish look like underwater?

At depth, a blobfish kind of just looks like a fish. They have slightly bulbous heads, pronounced black eyes and feathery pectoral fins. Their bodies, pinkish-grey in colour, taper to the tail a bit like a tadpole. Blobfish typically measure less than 30cm in length and weigh under 2kg.

How do blobfish swim?

With as little effort as possible. Like a lot of deep-sea fish, the blobfish doesn't have a swim bladder, the air sac-style organ that helps fish closer to the surface control their buoyancy. If they did, they'd be crushed under the pressure. Instead, the fatty body composition of the blobfish comes into play. It's actually less dense than the water it lives in.

"If you think about how oil floats on water, it's a bit like that: having high fat content means it makes them more buoyant," says Watt. Blobfish simply bob along in the water or on the sea bed, staying largely still and using as little energy as possible.

"It's labour-saving," Watt says. "Being lazy is a survival strategy, and being fatty to help being lazy is a survival strategy." We can all relate to that, surely.

What do blobfish eat?

Given their inherent lethargy, blobfish are thought to eat whatever passes right in front of them. Their neutral buoyancy means the water carries them along. When small crustaceans, sea snails or other edible matter gets too close, they become dinner.

This lie-in-wait strategy is common among deep-sea predators.

Read more about the deep sea:

• Deep sea mining: new depths
• Ancient deep-sea bacteria revived after 100 million years
• Toxic mercury found at the ocean's deepest point

Where do blobfish live?

The Psychrolutidae family is fairly widespread with species found in the Atlantic, Pacific and Indian Oceans. However, some species of blobfish – including the one nicknamed Mr Blobby – are found in fairly small territories.

Psychrolutes microporos (and its closely related cousin Psychrolutes marcidus) live in the waters around and between Australia and New Zealand, always at depths greater than 500m.

What do baby blobfish look like?

There are a number of fake pictures online, but it's not clear what baby blobfish actually look like.

Little is known about blobfish behaviour because it's hard to observe any creature when they live in the dark depths of the ocean. This includes mating, although marine biologists suggest that, given their limited movement, pairs might simply cling to each other.

Some Psychrolutidae species have been observed laying thousands of eggs, often on rocks that they patrol from nearby. Reports suggest that expectant mothers group together and nest near one another, presumably for protection.

How long do blobfish live?

This is a difficult question to answer as we know so little about these intriguing fish. However, we do know that marine fish that live in deep water tend to grow slowly, take a long time to reach maturity and have extended lifespans. For example, the rougheye rockfish, which lives at depths of 150 to 450 metres, can live for more than 200 years.

The blobfish and conservation

It's unclear whether blobfish are actually endangered, partly because it lives in the alien world of the deep ocean and we know so little about it. For example, we don't know how many there are, whether they have natural predators, how they're affected by ocean acidification or how long they live for.

"With the blobfish, it's questionable whether it's even endangered, but that's true of almost all fish," says Watt. "It's very hard to work out the territory of a fish. We do know that there's a risk from deep-sea trawlers."

If Psychrolutes microporos is limited to the region around Australia and New Zealand then its numbers are unlikely to be huge – but neither is the number of trawlers in that region. It's hard to know how much damage the population suffers when even a single blobfish ends up in nets, Watt says.

"We know that anything that lives in the deep tends to have long lives, so for example an orange roughy – which is a fish we do see on tables throughout Europe – reach maturity at around 30. Which means if you kill one now, it's 30 years before that population recovers."

Whether or not the blobfish itself is endangered, it has already done an effective job at raising awareness, thanks in no small part to Watt's poll of the world's ugliest animals and ongoing projects. His approach to conservation is deliberately irreverent, but the comedy belies a serious point. His website states that invertebrates, for example, make up 79 per cent of animal life, but they are only covered in 11 per cent of conservation literature. Ugly animals are less likely to be researched, never mind protected.

The blobfish may be unfairly painted with the ugly brush, but it still works as an effective mascot for Watt's work.

"Conservation is so depressing that we needed a silly way of talking about it," he says. "The people who know the giant panda are already on board. The people who have the blobfish as their spirit animal were not being talked to."

Read more about conservation:

• Why African black rhino numbers are increasing
• How China is creating Edens
• How safe are our marine protected areas?