Top 10 World’s Most Dangerous Fish
red-bellied piranhacredit: © Andro/Fotolia
Many people around the world depend on fishes or
products made from fishes for their food and economic livelihood. More
than 30,000 different species ply Earth’s oceans and bodies of fresh
water. The beauty of many fish species is highlighted in fish stores,
aquariums, and in home collections. Some species, however, have darker,
more terrifying aspects. A select few of these may attack human beings,
while others might deliver a dose of poison when handled carelessly or
not properly prepared for consumption. Some species are maligned due to
their shocking appearance or by their ferocious reputation in folklore
and myth; however, one species, though cute and tiny, threatens bathers
in a very, shall we say,
personal way.
10Puffer
puffer fishcredit: Photos.com/Thinkstock
The puffer, which is also called swellfish, or blowfish,
is any member of a group of about 90 species of fishes of the family
Tetraodontidae, noted for their ability when disturbed to inflate
themselves so greatly with air and water that they become globular in
form. Puffers are found in warm and temperate regions around the world,
primarily in the sea but also, in some instances, in brackish or fresh
water. They have tough, usually prickly skins and fused teeth that form a
beaklike structure with a split in the center of each jaw. The largest
puffers grow about 90 cm (3 feet) long but most are considerably
smaller.
Many species are poisonous; a highly toxic substance,
tetraodontoxin, is especially concentrated in the internal organs.
Although this substance can cause death, puffers are sometimes used as
food. In Japan, where the fishes are called
fugu, they must be carefully cleaned and prepared by a specially trained chef.
9Red Lionfish
red lionfishcredit: © katatonia/Fotolia
Lionfishes (Pterois) make up any of several species of
showy Indo-Pacific fishes of the scorpion fish family, Scorpaenidae
(order Scorpaeniformes). They are noted for their venomous fin spines,
which are capable of producing painful, though rarely fatal, puncture
wounds. The fishes have enlarged pectoral fins and elongated dorsal fin
spines, and each species bears a particular pattern of bold, zebralike
stripes. When disturbed, the fish spread and display their fins and, if
further pressed, will present and attack with the dorsal spines. One of
the best-known species is the red lionfish (
Pterois volitans), an
impressive fish sometimes kept by fish fanciers. It is striped with
red, brown, and white and grows to about 30 cm (12 inches) long. The red
lionfish is native to South Pacific reef ecosystems. In the early 21st
century the species became established in reef ecosystems along the
Eastern Seaboard of the United States, in the Gulf of Mexico, and in the
Caribbean Sea. Its rapid rate of reproduction, combined with the
absence of natural enemies in those regions, resulted in its decimation
of local reef fishes and its designation as an invasive species.
Wildlife managers suspect that lionfish were deliberately released by
pet owners into the ocean along Florida’s Atlantic coast starting in the
1980s, but damage to pet stores caused by Hurricane Andrew in 1992 may
have also allowed others to escape.
8Candiru
candirucredit: © Morphart Creation/COMEO—Shutterstock
The candiru, (
Vandellia cirrhosa), is a scaleless,
parasitic catfish of the family Trichomycteridae found in the Amazon
River region. It is translucent and eellike, and it grows to a length of
about 2.5 cm (1 inch). The candiru feeds on blood and is commonly found
in the gill cavities of other fishes. It sometimes also attacks humans
and has been known to enter the urethras of bathers and swimming
animals. Once in the passage, it erects the short spines on its gill
covers and may thereby cause inflammation, hemorrhage, and even death to
the victim.
7Great White Shark
great white sharkcredit: Copyright Ron and Valerie Taylor/Ardea London
The white shark (
Carcharodon carcharias), which is
also called great white shark or white pointer, may be the fish that
needs no introduction, because it is one of the most powerful and
potentially dangerous predatory sharks in the world. Starring as the
villain of movies such as
Jaws (1975), the white shark is much
maligned and publicly feared; however, surprisingly little is understood
of its life and behavior. According to the fossil record, the modern
species has been around since roughly 18–12 million years ago, during
the middle of the Miocene Epoch, but its ancestors may date back to at
least the Eocene Epoch (about 56–34 million years ago).
In the areas
where they are most common, white sharks are responsible for numerous
unprovoked, and sometimes fatal, attacks on swimmers, divers, surfers,
kayakers, and even small boats. A white shark tends to inflict a single
bite on its human victim and then retreat. In many instances, however,
the shark rarely returns for a second bite. If the victim suffers a
moderate bite, he or she may have time to seek safety. In situations
where a large bite occurs, however, serious tissue and organ damage may
result in the death of the victim. A review of white shark attacks off
the western United States showed that about 7 percent of attacks were
fatal, but data from other localities, such as South Africa, show
fatality rates of more than 20 percent. Fatality rates as high as 60
percent have been recorded from attacks in the waters off Australia.
Many
researchers maintain that attacks on humans stem from the shark’s
curiosity. In contrast, other authorities contend that these attacks may
be the result of the shark mistaking humans for its natural prey, such
as seals and sea lions. It is also possible that white sharks intend to
attack humans where their normal prey may be scarce.
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6Moray Eel
mosaic moray eelcredit: Darryl Torckler—Stone/Getty Images
There are probably more than 80 species moray eels, and
they occur in all tropical and subtropical seas, where they live in
shallow water among reefs and rocks and hide in crevices. Moray eels
differ from other eels in having small rounded gill openings and in
generally lacking pectoral fins. Their skin is thick, smooth, and
scaleless, while the mouth is wide and the jaws are equipped with
strong, sharp teeth, which enable them to seize and hold their prey
(chiefly other fishes) but also to inflict serious wounds on their
enemies, including humans. They are apt to attack humans only when
disturbed, but then they can be quite vicious.
Moray eels are usually
vividly marked or colored. They generally do not exceed a length of
about 1.5 meters (5 feet), but one species,
Thyrsoidea macrurus
of the Pacific, is known to grow about 3.5 meters (11.5 feet) long.
Morays are eaten in some areas of the world, but their flesh is
sometimes toxic and can cause illness or death. One species of moray,
Muraena helena, found in the Mediterranean, was a great delicacy of the ancient Romans and was cultivated by them in seaside ponds.
5Tigerfish
tigerfishcredit:
Painted especially for Encyclopædia Britannica by Tom Dolan, under the
supervision of Loren P. Woods, Chicago Natural History Museum
Spanning several species, tigerfishes are so named on the
basis of their pugnacity when caught, their fiercely predaceous habits,
or their appearance. In African freshwaters, tigerfishes of the genus
Hydrocynus (sometimes
Hydrocyon)
are admired game fishes of the characin family, Characidae (order
Cypriniformes). They are marked, depending on the species, with one or
several dark, lengthwise stripes and are swift, voracious, salmon-shaped
carnivores with daggerlike teeth that protrude when the mouth is
closed. There are about five species; the largest (
H. goliath) may be more than 1.8 meters (6 feet) long and may weigh more than 57 kg (125 pounds). The smaller
H. vittatus is claimed to be one of the finest game fishes in the world.
In
the Indo-Pacific, marine and freshwater tigerfishes of the family
Theraponidae (order Perciformes) are rather small and usually marked
with bold stripes. The three-striped tigerfish (
Therapon jarbua)
is a common, vertically striped species about 30 cm (12 inches) long. It
has sharp spines on its gill covers, which can wound a careless
handler.
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4Piranha
piranha: piranha eating a fishcredit: John Madere/Corbis
Piranha, also called caribe or piraya, are any of more
than 60 species of razor-toothed carnivorous fish of South American
rivers and lakes, with a somewhat exaggerated reputation for ferocity.
In movies such as
Piranha (1978), the piranha has been depicted
as a ravenous indiscriminate killer. Most species, however, are
scavengers or feed on plant material.
Most species of piranha never
grow larger than 60 cm (2 feet) long. Colors vary from silvery with
orange undersides to almost completely black. These common fishes have
deep bodies, saw-edged bellies, and large, generally blunt heads with
strong jaws bearing sharp, triangular teeth that meet in a scissorlike
bite.
Piranhas range from northern Argentina to Colombia, but they
are most diverse in the Amazon River, where 20 different species are
found. The most infamous is the red-bellied piranha (
Pygocentrus nattereri),
with the strongest jaws and sharpest teeth of all. Especially during
low water, this species, which can grow up to 50 cm (about 20 inches) in
length, hunts in groups that can number more than 100. Several groups
can converge in a feeding frenzy if a large animal is attacked, although
this is rare. Red-bellied piranhas prefer prey that is only slightly
larger than themselves or smaller. Generally, a group of red-bellied
piranhas spreads out to look for prey. When located, the attacking scout
signals the others. This is probably done acoustically, as piranhas
have excellent hearing. Everyone in the group rushes in to take a bite
and then swims away to make way for the others.
The lobetoothed piranha (
P. denticulate),
which is found primarily in the basin of the Orinoco River and the
tributaries of the lower Amazon, and the San Francisco piranha (
P. piraya),
a species native to the San Francisco River in Brazil, are also
dangerous to humans. Most species of piranhas, however, never kill large
animals, and piranha attacks on people are rare. Although piranhas are
attracted to the smell of blood, most species scavenge more than they
kill. Some 12 species called wimple piranhas (genus
Catoprion) survive solely on morsels nipped from the fins and scales of other fishes, which then swim free to heal completely.
3Stonefish
Synanceja verrucosacredit: Douglas Faulkner/Sally Faulkner Collection
Stonefish are venomous marine fish classified in the genus
Synanceja
and the family Synancejidae, found in shallow waters of the tropical
Indo-Pacific. They are sluggish, bottom-dwelling fish that live among
rocks or coral and in mud flats and estuaries. Thickset fish with large
heads and mouths, small eyes, and bumpy skins covered with wartlike
lumps and, sometimes, fleshy flaps, they rest on the bottom, unmoving,
blending almost exactly with their surroundings in form and color. They
are dangerous fish. Difficult to see, they can, when stepped on, inject
quantities of venom through grooves in their dorsal-fin spines. Wounds
produced by these fish are intensely painful and sometimes fatal. The
family Synancejidae includes a few other species of robust, warty fish.
They are also venomous, though not as notorious as the stonefish.
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2Atlantic Manta
manta raycredit: moodboard—moodboard/Thinkstock
Manta rays or devil rays make up several genera of marine
rays comprising the family Mobulidae (class Selachii). Flattened and
wider than they are long, manta rays have fleshy enlarged pectoral fins
that look like wings; extensions of those fins, looking like a devil’s
horns, project as the cephalic fins from the front of the head. Manta
rays have short whiplike tails provided, in some species, with one or
more stinging spines.
Manta rays, related to sharks and skates, are
found in warm waters along continents and islands. They swim at or near
the surface, propelling themselves by flapping their pectoral fins and,
at times, leaping or somersaulting out of the water. They feed on
plankton and small fishes that they sweep into their mouths with their
cephalic fins.
The smallest of the manta rays, the species
Mobula diabolis of Australia, grows to no more than 60 cm (2 feet) across, but the Atlantic manta, or giant devil ray (
Manta birostris),
the largest of the family, may grow to more than 7 meters (23 feet)
wide. The Atlantic manta is a well-known species, brown or black in
color and very powerful but inoffensive. It does not, old tales to the
contrary, envelop pearl divers and devour them.
1Electric Eel
electric eelcredit: Toni Angermayer/Photo Researchers
The electric eel (
Electrophorus electricus) is an
elongated South American fish that produces a powerful electric shock to
stun its prey, usually other fish. Long, cylindrical, scaleless, and
usually gray-brown (sometimes with a red underside), the electric eel
can grow to 2.75 meters (9 feet) and weigh 22 kg (48.5 pounds). The tail
region constitutes about four-fifths of the electric eel’s total
length, which is bordered along the underside by an undulating anal fin
that is used to propel the fish. Despite its name, it is not a true eel
but is related to the characin fish, which include piranhas and neon
tetras. The electric eel is one of the principal aquatic predators of
the whitewater flooded forest known as
varzea. In one fish survey of a typical
varzea,
electric eels made up more than 70 percent of the fish biomass. The
electric eel is a sluggish creature that prefers slow-moving fresh
water, where it surfaces every few minutes to gulp air. The mouth of the
electric eel is rich with blood vessels that allow it to use the mouth
as a lung.
The electric eel’s penchant for shocking its prey may have
evolved to protect its sensitive mouth from injury from struggling,
often spiny, fish. The shocked prey is stunned long enough to be sucked
through the mouth directly to the stomach. Sometimes the electric eel
does not bother to stun prey but simply gulps faster than the prey can
react. The eel’s electrical discharges may be used to keep prey from
escaping or induce a twitching response in hidden prey that causes the
prey to reveal its position.
The tail region contains the electric
organs, which are derived from muscle tissue enervated by spinal nerves,
and discharges 300–650 volts—a charge powerful enough to jolt humans.
These organs may also be used to help the creature navigate and to
communicate with other electric eels.