Imagine you are reeling in your catch and suddenly you see a fish that looks like it came straight from a science fiction movie. There are many strange fish that can be caught in our world’s waters – their appearance and behavior amaze even scientists. Some strange fish have glowing organs or giant toothy mouths, while others lose their eyes altogether due to living in the dark. However, all these features are not oddities for the sake of oddity, but rather advantages formed by evolution. Let’s analyze why fish sometimes look so unusual, and get acquainted with the strangest fish that can actually be caught in the world’s water bodies.

Strange fish you can catch in the world

Below, we'll take a look at specific fish species that are notorious for their strangeness. Many of them are something that fishermen may encounter – intentionally or unintentionally – in various bodies of water around the world. From deep-sea monsters to strange freshwater creatures, get to know the most interesting specimens.

Sea devil

Sea devil (lat. Lophius piscatorius) is a deep-sea predatory fish that looks like something out of a nightmare. Its huge head takes up almost half of its body, and its mouth is full of long, sharp teeth. This fish grows up to 1.5 m long and weighs 20 kg. The most interesting thing is that the forehead of the monkfish is “decorated” with a longitudinal barbel – this is an evolutionarily formed “fishing rod” with a glowing bait at the end. While lurking on the seabed among the rocks, the devil waves this bait and lures curious smaller fish straight into its jaws. This bait emits light in the dark (thanks to bioluminescence) – a great trick in the eternal darkness of the depths. Sea angels are found at depths of 50–200 m in the Northeast Atlantic, the Mediterranean and the Black Sea. Despite their frightening appearance, people fish for them: the devil’s tail is considered a delicacy (known as “monkfish”). Most importantly, however, this fish demonstrates astonishing adaptability, as it stalks prey in complete darkness using its "fishing prowess."

Pufferfish

Pufferfish (lat. Tetraodontidae) – a seemingly cute, round fish, which is actually one of the most poisonous in the world. It got its nickname “bubble” because when it senses danger, it instantly swells into a spiked ball. The skin of the pufferfish is covered with upright spines and it floats belly up – it is almost impossible for a predator to swallow it. Even more impressive is that the tissues of many pufferfish contain tetrodotoxin – an extremely strong poison, which is even 1200 times more toxic than potassium cyanide. One of the most famous pufferfish – pufferfish (Takifugu niphobles), is considered a delicacy in Japan. Chefs prepare fugu very carefully, because the slightest mistake can be fatal - the poison of this fish paralyzes the nervous system. The pufferfish family includes ~185 species living in tropical waters. In their mouths are four strong teeth, forming a beak-like structure, with which they crush corals and mollusk shells. Interestingly, pufferfish, which are seemingly slow-moving, have another talent: some species (e.g., the white-spotted pufferfish) are able to decorate sand “artistic” nests on the seabed to attract a female. So this pufferfish is like a cute but deadly sea urchin, endowed with natural defensive features.

Albino catfish

Catfish albino – this is not a separate species, but a rarity: an individual of a common catfish, which due to a genetic mutation has no pigment. Albino catfish have milky white skin and pink eyes – such a sight is stunning, as if you were seeing a ghost in the river. The most common albinos are big catfish (Silurus glanis) relatives that usually live in Europe. Since albinism reduces camouflage, to survive In the wild, albinos have a hard time: bright white fish are easier to see by predators, and the predatory albino catfish itself has a harder time hiding when lurking for prey. As a result, such individuals are extremely rare in the wild (it is estimated that only ~1 in 10,000 catfish are born albino).

However, there are impressive incidents: in 2013, a British fisherman in Spain caught a giant white catfish measuring 2.5 meters long and weighing 93 kg - at that time it was a world record. After a tense 30-minute fight, the giant was pulled out, captured in photographs and released back. Albino catfish are viewed ambiguously: for some it is a dream trophy, for others - a natural rarity that should be protected. Scientists note that albinism is only a change in appearance, which does not affect the meat or taste of the fish. However, due to rare genes, it is worth admiring and releasing it - may it continue to swim in our waters as a living miracle of nature.

Vegelė

Vegelė (lat. Lotta lotta) is the only codfish in the world that has adapted to living in fresh water. For this reason, fishermen sometimes call the wrasse “freshwater cod”. Its body is long and slimy, resembling a hybrid of an eel and a cod: a flat head, a mustache on the chin, thick and slippery skin, covered with small ingrown scales. The mottled yellowish-brown pattern helps it to camouflage itself among the stones at the bottom. The wrasse is an active predator, but only in cold weather. Unlike most fish, it likes the cold: in autumn and winter, when the water cools to +4 °C or less, the wrasses come to life. They hunt at night, accompanied by darkness and bad weather - then they slowly sneak up on their prey and swallow it. In summer, when the water warms up, the wrasses hardly feed and even burrow into the mud, as if they were summering.

Another unique feature is that these strange fish spawn in midwinter, under the ice, when the temperature is ~1–3 °C. During spawning, the wrasses go to the shallows even in the cold, when other fish are inactive. Due to the atypical rhythm of life in Lithuania carp fishing also unusual: They are only allowed to be caught at the end of winter (from February), as spawning occurs in December-January, and it is prohibited to catch fish smaller than 45 cm.. From a culinary point of view, the bream is highly regarded – its meat is white, low-fat, and its liver is considered a delicacy. Even if you are not a winter fishing enthusiast, it is worth knowing about this strange fish, which resembles a nocturnal shadow of cold waters more than a common inhabitant of our lakes.

Thorny shark

Thorny shark (lat. Squalus acanthias) is a small shark adorned with sharp spines. This species of shark grows to only ~1 meter in length, but has two poisonous spines - one in front of each dorsal fin. If someone attacks a stingray, it can strike with its spines and inflict a painful wound, injecting a small amount of poison. Stingrays are common in temperate waters of both the Atlantic and Pacific Oceans, often near the seabed. Interestingly, these sharks are also sometimes caught by our fishermen in the Baltic Sea: in 2018, a fisherman near Liepaja caught a ~1 m long stingray - the fish surprised him, because sharks are very rare off the coast of Lithuania. Realizing what a rarity he had caught (this species is endangered), the fisherman photographed the shark and released it back into the sea.

By the way, stingrays have another unique feature – they the longest pregnancy duration among all vertebrates. The female carries her young for up to 2 years (22-24 months) before giving birth to fully developed young. Such slow reproduction means that it is difficult for the population to recover, which is why the number of dogfish has decreased in many places due to overfishing. However, in some places (for example, in the British Isles) they are still caught and eaten, called “rock salmon”. Whether you meet a dogfish in the Baltic Sea or elsewhere - remember that this is a unique small shark with “spikes” that requires our responsible approach.

Algae

Algae (lat. Bald eagle), is a true living fossil in the freshwater world. It is the only surviving species of the ancient Amiiformes order. Its appearance resembles a primitive fish: the body is up to 70 cm long, cylindrical, thickly covered with mucus; the back is lilac-brown with a marble pattern, and the fins are soft. Although the mudfish is similar to other bony fish, its structure has preserved archaic features - for example, it has primitive lungs. More precisely, the swim bladder functions as a lung: the fish can inhale air and breathe it! It even regularly sticks its head above the water to breathe air – even if the water is sufficiently oxygenated. This unique adaptation allows the mudfish to thrive in shallow, marshy ponds where oxygen is lacking in the summer – places where other predatory fish would not survive.

The mudfish is widespread in North America (in the Great Lakes and Mississippi basins) and prefers algal, densely vegetated waters. It is active mainly at night - then it hunts smaller fish and frogs. Interestingly, during breeding, the male mudfish builds a nest of grass in the shallows and protects the female's eggs there, and later the hatched larvae. This is a rather rare paternal behavior among fish predators. When you catch a mudfish, you may be quite surprised - this relict fish fiercely resists. It has sharp teeth and can even bite - American fishermen joke that the mudfish "defends the legacy of the dinosaurs". Although this fish is poorly regarded for food (the meat has many small spines), fishing for it provides a lot of excitement in a sporting sense. A mudfish can live up to 30 years, so by catching one, we are catching a piece of the past - a species that swam back in the days of dinosaurs.

Silver carp

Ssilver carp (lat. Hypophthalmichthys molitrix), an invasive species of carp with an unexpected talent for “flying”. These carp live in rivers and lakes, feed on plankton, but when frightened, they behave unusually: they jump out of the water up to 3 meters high! A passing motorboat causes a mass reaction – dozens of large fish can jump into the air right around people. In the USA, there have been cases where a 10 kg silver carp, jumping and crashing into a person in a speedboat, broke his jaw and caused a concussion.

“Flying Carp” has become so problematic that water sports have become dangerous in some rivers - water skiers in the Mississippi are taking a serious risk, as these strange fish simply fly around them. Why do silver carp jump like this? It is believed that this is an escape reflex - in nature, jumping movements help them escape from predators, and the noise of boats confuses them. The unusual behavior of silver carp is shocking to those who see it for the first time. It is also interesting that the Chinese themselves consider silver carp a delicacy - so this salmon-jumper poses a threat to tourists in one place, and in another - steaming on the dinner tableWhatever the case, the reality of flying fish proves that real "flying fish" exist in nature.

Glass fish

Glass fish – when you look at such a fish, you seem to see its skeleton and internal organs! One of the most famous – Indian glass perch (lat. Parambassis rank). Also known as glass catfish (lat. Kryptopterus vitreolus), a favorite aquarium pet. The skin and muscles of these fish are almost transparent - in nature this helps them hide from predators, as if dissolving in the water. For example, the body of the glass catfish is almost completely transparent, only the spine is visible, and a shiny silver bag near the head - opaque internal organs are concentrated there. However, when you look through the fish, you can see its bones, as if in an X-ray. Glass fish are usually small (5-10 cm), live in tropical rivers (e.g. in Southeast Asia). Their characteristic feature is cowardice: they like to stand in groups in murky water, upstream, lurking for small shrimp or insects. Interestingly, in aquariums, these ghostly fish are often artificially painted in bright colors - colored "glasses" look more beautiful to people, although this is harmful to them.

Sword-wielding berkis

Sword beryx - (lat. Anoplogaster cornuta), a deep-sea fish whose teeth look incredibly large. Fangtooth means “fangtooth” in English – in fact, this ~17 cm long fish has teeth comparable to shark teeth, although it fits in the palm of your hand. The fangs of its lower jaw are so long that they stick out even when it is closed. Nature has “solved” this problem: there are special pockets at the top of its mouth into which the fangs slide. Living at a depth of 500–2000 m, in absolute darkness, this fish cannot afford to miss even the slightest prey – that is why it has such weapons. By the way, relatively (compared to body size) these are the largest teeth among all fish in the world.

The swordtail beryx is found at depths of up to 5,000 m – it is one of the deepest-living fish in general. During the day, it stays in the depths, and at night it rises closer to the surface to feed (such vertical migrations are typical of many deep-sea creatures). Young beryx feed on plankton, and adults attack almost anything – fish or squid. Their eyesight is poor, so their lateral line helps them detect prey. Although it would seem that such a fierce predator should be, it is actually quite slow – there is little food in the depths, and they have to save energy. Zoologists have kept this fish in an aquarium under high pressure, and it has managed to survive for several months. Its repulsive smile seems to shout “I am a monster”, but in reality it is just another amazing creation of evolution, adapted to thrive where others would not survive.

In conclusion

In short, we learned that strange fish are not necessarily rare - you just have to look closely. The environment has shaped fish for millions of years, giving them the strangest "tools": glowing antennae, poisonous spines, inflatable bodies or even the ability to change sex. For a fisherman, this means that any fishing trip can bring surprises. When you meet an unusual fish, treat it with respect - maybe it's the most beautiful catch of your life, which is best released back to live on. At the same time, let's not forget about humor - after all, fishermen's stories about the "scariest fish" or the "flying fish" can be completely true! Nature has a good sense of humor, giving us the opportunity to catch something that will make us gape in amazement.

If you enjoyed this journey through the world of strange fish, don't keep the impressions to yourself. We invite you to share article with your friends who are fishermen, nature enthusiasts or those who need proof that “fishing is not boring”. Maybe next time your friends will go looking for those mysterious catches together? The underwater world hides many more secrets – let's share our knowledge and passion for exploring nature! Let as many people as possible learn about the incredible creatures that swim in rivers and oceans!