Vampire Fish: Characteristics,types, habitat and more

Today we will meet an impressive predatory fish: The vampire fish or «Scomberoides Hydrolycus»; a species of fish popularly known in its home habitat as –toothed tiger fish» and «water wolf.»

Hydrolycus armatus commonly called Payaras or freshwater vampire fish in the aquarium hobby, is one of the world’s largest tetras.


Phylum: Chordata Class: Actinopterygii  Subclass: Teleostei Order: Characiformes Family: Cynodontidae Gender: Hydrolycus Species: H. armatus


The Vampire Fish’ Main Characteristics

The physical appearance of this fish is powerful as it has a robust and laterally compressed body.  Their fins are short but have strong muscles which allow them to swim very quickly if their prey undertakes the escape.

However, the payara fish’ (as they are known in Spanish) most striking trait is undoubtedly its spectacular mouth, considered a powerful machine to tear their prey apart,.

The lower jaw is longer than the upper jaw, and both are armed with pointed sharp teeth from those used to crush their victims.

The attacking method and physical appearance is quite similar between the Payaras and the Goliath Tigers fish, since their heads are very similar. In addition, these two species can naturally replace their teeth and their four-part jaws allow them to open the mouth very broadly in both cases.

The vampire fish, thanks to their good eyesight, hide deep in the fast and murky waters by launching ambush attacks on their prey, which makes of them a deadly and perfect machine, and they do so with lethal and diabolical precision.

The Vampire Fish’ Size and Weight

In nature, vampire fish can become quite large. They measure anywhere from 2 – 3 feet long, and their weight is around 10 – 35 pounds. The largest recorded came in at 40 pounds.

Captivity is another story. When bred in aquariums, vampires rarely exceed 12 inches and 5 – 10 pounds.

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Habitat and Distribution

This is a freshwater fish of tropical climates which ivampire fish: species belonging to the Hydrolycus genuss found  in the Amazon and Orinoco river basins, and Guyana Rivers.

Other Hydrolycus species

    • Hydrolycus armatus
    • Hydrolycus tatauaia
    • Hydrolycus wallacei



In the wild, vampire fish are ferocious hunters that are constantly looking for their next prey. They’ve been known to chase off medium- and large-sized fish that they don’t want to eat just so the water will be clear for the fish that they do want to consume.

In terms of compatibility they may tolerate others payaras in small groups, but they’re mostly lonely creatures. It’s assumed that they only come together for mating and migrating.

Captive payaras take these antisocial tends up to 11. They don’t like to be housed with other fish at all, and they’ll fight, threaten, charge and kill species that are put in the same aquarium. They hate being crowded.

They’re moody and temperamental fish on a good day, but when you force to defend their territory, they become aggressive as well.

It’s recommended that only experienced fish owners try their luck with vampire. They definitely aren’t first-time fish.

How Vampire Fish Reproduce?

The Vampire fish have never been bred in captivity; for this reason not much is known about the courtship and spawning behaviors of Hydrolycus species.

However, Payara are migratory fish which start reproducing with the beginning of the rainy season.

They move from lakes and river channels in the rising waters of large rivers, migrating long distances upriver for spawning and feeding. Presumably, it would be difficult to reproduce them in an aquarium and would require a very large tank.

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What Do Vampire Fish Feed On?

The vampire fish are characterized by being extremely aggressive, voracious, and very fast fish, which makes them true hunting machines.

They usually swallow their entire prey, although sometimes they only bite their prey with their powerful tusks, tearing large pieces and then swallowing them.

Vampire fish usually eat all kinds of food, although they prefer a carnivorous diet. So they devour smaller fish found in their territory.

Yet the vampire fish’ favorite food, are the fearsome piranhas , which fully swallow of a single bite.

Fishing Vampire Fish

In order to fish  payaras in the strong currents of the rivers where they inhabit, a suitable fishing equipment is essential. Lines should be about 40 to 60 pounds, with high-powered brake reels and enough yarn for about 500 to 1000 yards.

These requirements may seem a little exaggerated, but you will realize soon that they are totally necessary, since this a very strong and you’ll be setting against very turbulent and fast waters.

In terms of lures, wooden ones such as the Rapala Countdown Magnun are preferable. You can also use live bait which will depend on the type of fishing you want to carry out.

To fish in a backwater near the stream with float or bottom, you must choose live fish or bait and if on the contrary you want action from a boat, we will choose lance rods and artifici

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Other Vampire Fish Species.

Let’s meet another fish also called Vampire

Candiru (Vandellia Cirrhosa)

This is perhaps one of the smallest fish that we can find in the Amazon river specifically in the rivers of Brazil, where candirus are popularly known because of the effects they cause when people urinal within the waters (especially men).

Despite their harmless appearance, candirus can cause very significant damage to the men’s reproductive system.

Main Characteristics

There are two species of candirú that can be found in the waters of the rivers of the Amazon.  In general they are gray, with a white belly and a rear fin with colors between black and red. On the other hand, there is a species that is slightly browner, with a green back fin

Candirús have 5 fins in total, the largest being the last two; the upper and lower ones are paramount for adapting to the currents of the rivers.


As for their head it is flat and a little wider than the rest of the body.

It has whiskers that allow them to detect the water’s temperature as well as differentiate between odors and environmental changes that may occur.


While it is true that it is one of the smallest fish species that we can find, they have managed to obtain specimens up to 22 cm long, being completely transparent, very different from those already known and described.

Where do Candirús Inhabit?

These specimens can be found in most of the rivers that make up the great Amazon, however, the greatest number of sightings and perhaps the largest population in the world is located in Brazilian waters.

Their favorite place are those that have a good depth, in addition to being fans of the strong currents and tides, so they are amazing swimmers. It’s  important to mention that candirús are especially freshwater fish.

What do Candirus Feed On?

The candirús’ scientific name is Vandellia Cirrhosa, their favorite food, (despite their bad  reputation), are other fish smaller in size or even of similar sizes to theirs,  since in fact they are scavenger fish , like their distant relative the catfish

Another candirus’ attacking method is to get inside the gills of other fish to begin the process of feeding from the inside out.

Why are Candirú Fish So Dangerous?

There are many myths and legends that run around this interesting creature, from the fact that they feed on human genitalia, to that they are small wild beasts capable of devouring any kind of prey in seconds.

The truth is that, for the most part, they are unfounded myths, urban rumors and gossip  belonging to the rural populations that reside near the water sources of the Amazon.

They are certainly considered dangerous animals for human beings due to their own recklessness, since urinating inside waters of the rivers is their main source of attraction.

Candirus manage  to smell at really important distances the urine’s toxins. The urine trail leaves the way clear so the fish can get a new place to adapt to live and start feeding.

These facts, although certainly remote, take place in some Brazilian waters and the candirus’ operating method is to enter completely wildly into the scrotum of men.

This causes indescribable pain and the person can instantly perceive that the animal crashed into the entry of the sex organ.  Although it does not occur with the same frequency, women also suffer from these attacks which can even enter by the anus with the intention of feeding.

The clearest symptoms that can be witnessed about this body invasion, is extremely intense bleeding and pain, which are very dangerous for anyone’s life.

In the unlikely event that the panicked victim managed to grab the fish, its tips, probably hooked inside the urethra backwards, would cause pain as unbearable as indescribable in each tug, that could become dramatic for the person..

Once completely inside, the parasite follows its path until it finds a good blood membrane with which to spread its fangs over the surrounding tissue and begin to celebrate once again.

But the horror movie doesn’t end here. For candirús, this wrong journey into a man’s penis is the last. The bloody feast ends up leaving him so swollen that he can’t escape through the hole.

According to the legend of the victims, many men chose castration as an alternative to a slow, death before surgery was an option.

What do Experts Think about these Fish?

As George Albert Boulenger, curator of Fish at the British Museum in the early 20th century, wrote, «the verdict of all existing accounts of these attacks is that the only way to prevent it from reaching the bladder, where it causes inflammation and finally death, is amputating the penis.»

However, Boulenger did not witness any attack directly, as did Gudder. In 2002 and in order to end (or not) the legend, a group of researchers from the University of Connecticut led by Stephen Spotte devised a plan.

The team reasoned that, since the fish can be successfully fed in muddy and turbulent waters (many times at night), they should have refined sensory adaptations that allow them to detect flavors and smells characteristic of their prey.

They then evaluated the fish with another live fish with attractive chemicals (such as ammonia). The result? He responded with «appetite» to the fish, but ignored any chemical signs.

The researchers then pointed out that there must be another reason for the alleged human attack.

At this point we return to the history of Silvio that took place in 1997. It is the only first-hand test available to medical literature. Spotte decided to go to the doctor who treated Silvio in Manaus (Brazil).

The man was fortunate to have access to modern medical facilities, although he had to endure three days of deep agony before the fish was extracted by the urogenital surgeon, Anoar Samad.

Apparently, Samad presented him with photos and even a video of the operation, but Spotte still doubted it. As he has claimed in a later work, the victim claims that the candirú had ascended by its urine stream before clinging violently to its urethra.

Spotte indicates that it is quite incredible, as «to swim through the stream of urine, the fish must do it faster than the force of the jet and get out of the water against gravity».

In short, the idea of the fish swimming and entering completely into a penis seems to go against the very laws of fluid dynamics. Verified reports of candirú attacks on human genitalia are so scarce that it is hard to believe that a fish is able to swim to a stream of urine from above and penetrate the penis.

So the logical thing to do is to think that if you urinate in the Amazon while your genitals are submerged and exposed, the risk is, at the very least, ridiculously unlikely.

Curious Facts about Candirus

    • Although they have a parasite shape, the truth is that candirús are very close relative of catfish.
    • They are fully scavenger fish, so they are always at the bottom of the rivers, near the mud.
    • Once candirus have managed to get into a person’s body, taking it out poses a real challenge for doctors.
    • They are also known as blue candirus, canary or vampire fish, and genitalia devourers.
    • They usually fed on the blood of other fish.
    • Perhaps one of the protective measures against this species of fish, is to bathe completely protected, that is, not to enter the waters with very loose clothing, but on the contrary, with swimsuits that can be adjusted perfectly to body, preventing their entry.
    • Finally, it’s advisable that no physiological activities be carried out inside the waters, because the candirus are attracted by the smells of toxins of our body.

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