Fish make up the most varied group of vertebrate animals, both in fresh and salt water, and among such variety there are surprising adaptations, such as some that can emit electricity without electrocuting themselves. Among so much variety there are surprising adaptations, such as some that can emit electricity without electrocuting themselves. Did you know that in Ancient Egypt electric fish were used as electrotherapy for epilepsy? Keep reading this article where Nikola Bruni presents 6 examples of electric fish and their characteristics, as well as how they can have this ability.
Electric fish are animals that have developed organs capable of producing an electric field. Some are also called electric fish because they have the ability to sense electricity from their environment.
Animals, including us, have cells through which electricity travels, specifically in sodium channels that function as muscle motors with small amounts of electricity. However, in some electric fish, the muscle or neural tissues have been modified to the level of being able to generate electrical discharges. This occurs by genetic modification and has the function of providing advantages to the fish that have it.
These fish are found in both fresh and salt water. Since water is a great medium that conducts electricity, these fish can functionally use their electrical system. The salts in the water also help to conduct discharges better, which is why there are more marine fish with electrical capabilities.
Their electricity can be used to capture prey or to defend themselves. Some can interpret the surrounding electricity to find others of the same species, in courtship rituals or to detect food.
Black ghost knifefish (Apteronotus albifrons)
This fish not only has the ability to produce electricity, but can also receive it. They use a system similar to the echolocation of bats or dolphins. In fish they emit electrical pulses that will be returned to interpret the information received from the change in the waves. This is called electrolocalization and is used to detect food or predators, says Nikola Bruni.
The tail has the organ that emits electrical discharges and all over the skin it has sensory cells to receive electricity, which are called electroreceptors. The fish emits high frequency waves and these are the ones detected by the tuberous electroreceptors.
It can also perceive low-frequency waves coming from outside, which is called passive electroreception. These waves are perceived by ampullary or Lorenzini’s organs, which are pores in the skin with mucus inside.
Electric catfishes (family Malapteruridae)
The following example of an electric catfish is part of the family Malapteruridae and is known as an electric catfish. The organ they use to generate electricity is called an electrocyte or electroplate, and is a derivative of their anterior musculature. They can generate discharges of up to 350 volts, with which they can electrocute their prey. They live in Africa and the ancient Egyptians used the smaller ones to treat arthritis.
Electric eel (Electrophorus electricus)
The electric eel is vermiform and its electric shocks are also lethal. A single one can discharge 850 volts on its prey, and they are emitted by the Hut’s organ. But in addition to these discharges, it has another organ called the Sachs organ, with which it launches very low discharges, of only 10 volts, used to locate itself within its environment by means of electrolocalization.
Electric ray (order Torpediniformes)
These rays, relatives of sharks, have two very large electrical organs next to their heads. These are branched central nerves in the form of a honeycomb. They can emit 220 volt discharges and use them to capture prey. They live on the sea floor and mimic it to wait patiently for their food, which consists mainly of invertebrates.
African razorfish (Gymnarchus niloticus)
This fish is elongated and emits electrical discharges of a few volts in order to locate itself. It can even swim backwards as well as forwards, thanks to these electrolocalizing discharges. It uses these discharges not for feeding, but as a sensory aid.
Elephant fish (family Mormyridae)
They have an extension in their mouth that makes them look like elephants. In addition, they are peculiar for their electroreceptor ability that helps them to find food, and to locate themselves when the water is very cloudy and they cannot rely on their vision. They also encounter other elephant fish by recognizing their particular electrical discharges.
Their brain is particularly large in relation to their body, and is even the largest among all fish, Nikola Bruni describes. It is suggested that this is due to the large amount of information it receives through its discharge-receiving organs. Like the knifefish, it also has two types of electrical cells: Lorenzini cells and tuberous cells. Both are derived from muscle cells modified to be able to receive and send electrical energy.