There are a number of fish able to produce electric currents of varying levels of voltage. Several species of fish such as the Peter’s Elephantnose Fish and Black Ghost Knifefish produce weak currents, typically less than a volt in strength, and use them mostly to navigate muddy waters and communicate.
On the other hand, we have fish like electric eels, which can generate a current of upwards of a hundred volts, killing or stunning prey and potential predators and making divers justifiably wary of meeting one of these fish at close quarters. But how do these electric fish generate all of this power?
How Electric Fish Produce Charge
All electric fish have specialized organs in their bodies, made up of specialized muscle cells called electrocytes. To regulate electrical discharge, they also have a special trigger organ known as the pacemaker nucleus, a specialized group of neurons in the fish’s brain. When the fish wishes to produce an electric current, it triggers the pacemaker nucleus, which sends a signal to the electocytes initiating electrical discharge. The electrocytes then use transmitter proteins to move positive sodium and potassium ions out of the cell, building up an electrical charge.
The individual amount of electricity generated per electrocyte cell is small. However, when millions of electrocyte cells function simultaneously, an electric fish is capable of building up charges of hundreds of volts.
Since the more electocytes an electric fish has the greater the voltage they are capable of producing, it’s unsurprising that the fish with the largest electrical organs are capable of generating the greatest amounts of electricity. An electric eel has three pairs of electric organs that take up nearly four fifths of its body, letting it generate extremely strong electric charges. Electric rays have a very large electrical organ on either side of their body that runs nearly from nose to tail; electric catfish have electric organs that line their entire body cavities.
So how do electric fish produce so much electricity? The answer is specialized muscle cells and clever chemistry. Check out this NatGeo footage of the electric eel in action!
5 Types of Electric Fish
Remarkably there exist quite a few species of marine creatures that generate electricity. These creatures possess an electric generating organ that is used as an offensive organ to help hunt down food, or as a defensive organ to protect themselves from larger predators. While most species that can generate an electrical discharge are below the 1 volt mark, we have compiled a list of the 5 most shocking underwater creatures which will make you think twice before donning that scuba diving equipment.
1. Electric Eel (370-650 volts)
The electric eel tops our countdown as being the number one underwater creature with the ability to generate the greatest electric current from its body.
Though called the electric eel, this creature does not belong to the family of eels but a species of knifefish which is a close relative of the catfish. Found primarily in the muddy bottoms of the fresh waters of the Amazon and Orinoco river basins in South America, these shocking creatures can generate a powerful electric current of up to 650volts to paralyze or kill its prey. Just to put this into perspective; this is 5 times the shock you would get from sticking your finger into an electrical socket. Generally 100-300 volts can shock the heart into defibrillation if the path of the current flows through the heart. A higher voltage will probably stop the heart. Electric eels have been known to stun animals as large as horses as they attempt to cross the river.
2. Electric Catfish (350-450 volts)
The electric catfish which has around 18 freshwater catfish species native to the Nile in Africa, can grow up to 1.2 m (4 feet) in length and 20 kg (45 pounds) in weight. This creature is capable of generating and controlling the discharge of up to 450 volts of electricity. It uses its power to defend itself and to capture prey. The electric organ is composed of modified muscle tissue and forms a fine, gelatinous layer directly beneath the soft, naked skin of the fish. Though the shock an electric catfish can generate is enough to kill a human, there are no documented cases of human fatalities caused by the catfish which would require repeated discharges to be fatal.
3. Electric Ray (37-220 volts)
Electric Rays belong to the family Torpediniformes which is derived from the Latin word ‘torpere’ which mean to stun or paralyze. These flattened cartilaginous creatures have the potential to produce an electric discharge ranging from 37 volts right up to a staggering 220 volts. Ranging from 6 inches these underwater stunners can grow to a length of 6 feet long and weigh up to 200 pounds. Like most rays electric rays are bottom dwelling and slow moving creatures relying heavily on their tails. They feed on invertebrates and small fish and lie in wait for prey below the sand or other substrate, using their electricity to stun and capture it. The common torpedo has five bright blue, dark-edged spots on its back making it easily recognizable.
4. Electric Stargazer (50 Volts)
Stargazers possess a large upward-facing mouth in an equally large head and have their eyes on the top of their heads, giving them their name. Their usual habit is to bury themselves in sand, and leap upwards to ambush prey that passes overhead. Some species have a worm-shaped lure growing out of the floor of the mouth, which they can wiggle to attract prey’s attention. Electric Stargazers possess their electric organ behind each of their eyes that is capable of generating up to 50 volts of electricity which is more than sufficient to stun or kills its prey.
5. Skate (4 volts)
This flat cartilaginous creature makes our list at the bottom, being able to generate 4 volts of electric discharge from their rather weak electric organs. Many studies have shown that the Skate uses its electric discharge more as a method of communication than to stun its prey or defend it. The skate contains its electric organ inside its tail and several of the approximately 100 species in the skate family are capable of emitting electrical charges. Found in most seas, it remains close to the seabed and burrows into it to conceal itself when resting. The skate can create a vacuum between itself and the bottom of the sea, producing suction that makes it difficult for predators to move the fish. Skate can measure anywhere from 1 foot to more than 20 feet, depending on the species (the largest skate is the manta ray).
