Buzz
Over 30,000 species of creatures generally referred to as “fish” have been identified, with some evolving in such odd ways that it’s almost unbelievable they share any common ancestry. The depths of the Earth hide strange and enigmatic beings.
10. The Sightless Waterfall-Climbing Loach
Living in the deep, subterranean caves of Thailand, Cryptotora thamicola is a troglobite that has completely lost its eyes and pigmentation in its dark, cavernous home. What sets this cave-dwelling fish apart, however, is its affinity for rapid currents and even climbing vertical surfaces. Its large, rugged fins allow it to securely grip smooth rocks without being swept away and even climb the rocky surfaces behind waterfalls.
9. The Tripod Fish
This abyssal oddity is one of the rare examples of a stationary, suspension-feeding fish—similar to corals, sponges, anemones, and other sea creatures, it simply stays in one spot, waiting for plankton to drift within its reach. Three of its fins extend into long, slender poles, enabling it to prop itself up in the muck of the deep ocean floor, where it can remain for days. It only moves when absolutely necessary, using its two front fins to capture food and guide it into its mouth.
Since they don’t need to hunt for food, tripod fish are nearly blind, and due to their rare encounters with each other, they are simultaneous hermaphrodites—meaning that any brief meeting between two adults could result in mutual impregnation.
8. The Stargazer
The Uranoscopidae, or “stargazers,” are a group of ambush predators with upturned, pug-like faces that allow them to bury most of their body beneath sand or mud, waiting for another unsuspecting fish to wander too close. When the opportunity arises, the stargazer snaps open its jaws, transforming into a deadly sinkhole that can swallow fish almost as large as itself.
Certain species of stargazer can even lure prey using a long, worm-like tongue. Some have a pair of venomous spurs behind their head, while others possess an electrical organ between their eyes, capable of paralyzing small prey and delivering a painful shock to any unwary human wader. It’s like a bundle of fish powers, all combined into one savage, underwater trap.
7. The Terrestrial Catfish
The rare and little-understood genus Phreatobius is believed to be the only type of fish that lives entirely on land, slinking through moist leaf litter along stream banks. Pink, slimy, worm-like, and seemingly blind, these creatures likely spend much of their existence buried beneath the soil. Beyond that, little is known about them.
6. The Tonguewhale
The Pleuronectiformes, or “flatfish,” are already among the most bizarre vertebrates on Earth. Though they begin life looking fairly typical, their skulls slowly distort as they grow, until both eyes are on the same side of the body, allowing them to lie flat and blend into the surroundings like a predatory rug in your bathroom.
The tonguewhales, also known as tonguefish or tongue soles, are even more specialized, having completely lost their pectoral fins and evolved a smooth, teardrop-shaped body. In many species, an extended lip or snout curves around the front of the jaws, giving the mouth a strange appearance as though a toothed hole cuts straight through their two-dimensional form. This unusual feature helps them capture small, soft-bodied prey from all sides simultaneously.
5. The Wolftrap Fish
The Thaumatichthyidae, or wolftrap anglerfish, might have the most comical overbites in the animal kingdom. While the upper jaw is often many times larger than the lower, it can also fold in half lengthwise, creating a cage to trap its prey and allowing the wolftrap fish to suck a meal down its throat. Each member of the Thaumatichthyidae family even has a bioluminescent lure dangling from the roof of its mouth.
Like other deep-sea anglerfish, they follow a parasitic mating practice: the male attaches himself to the female’s body, losing all unnecessary parts of himself in the process.
4. The Mudskippers
We’ve encountered a rare and little-known fish that slithers on land, but the most famous amphibious fish is the mudskipper. These gobies spend more time crawling across muddy shores than they do submerged in water—they can even move faster on land than in water. Their large gill chambers store water for long periods, and as long as they stay moist, they can breathe directly through their thin skin.
Male mudskippers are extremely territorial and engage in absurd battles for dominance, characterized by frantic flailing and biting.
3. The Tube-Eye
Also referred to as a thread-tail, Stylephorus chordatus is an extremely rare deep-sea fish so unique that the single species occupies its own entire taxonomic order. To put this into perspective, all the world’s cats, dogs, bears, raccoons, ferrets, and their relatives belong to one order, Carnivora. Imagine if none of these existed except for a single rare species of weasel in the world—this is similar to the situation with the tube-eye.
Despite its name, the most unusual aspect of this creature is likely its mouth. Aside from a tiny, tubular opening, its jaws are fused together with an expandable skin pouch that functions like bellows, or an accordion. By inflating this pouch, it generates a strong suction through the tiny opening to consume microscopic planktonic crustaceans. This same action also makes its eyes bulge and twist forward, resembling binoculars, allowing it to focus on its tiny prey.
2. The Walking Batfish
Resembling the bizarre offspring of a toad and a chicken skeleton, members of the Ogcocephalidae family are so specialized for life on the seafloor that their fins resemble legs, allowing them to walk through the sand in search of bottom-dwelling food. A distant relative of the anglerfish, they often feature a retractable lure just above the mouth, sometimes protruding from a nose-like extension.
1. The Whipnose Anglerfish
We’re already familiar with how bizarre deep-sea anglerfish can be, but members of the Gigantactinidae, or whipnose seadevils, are remarkable for two unusual reasons. First, their natural fishing lures grow to extraordinary lengths, sometimes stretching more than 10 times the length of the animal’s entire body. Even more puzzling, all known specimens of these creatures have been observed swimming upside-down. Why? No one knows.
