I was kindly asked to answer a similar answer in Portuguese, at Resposta de Sergio Diniz para Sergio Diniz, qual e o mecanismo biologico que gera essa energia eletrica nas enguias ? Alguem ja, estudou itso? This question has never been studied. So, I’ll translate it here.
First, thank You Jose Alberto Dietrich Filho For the question. I am fascinated by electric eels or more accurately electric fishes. Their bodies look like eels, but they are fish of the Gymnotiformes Family, which is closer to catfish and carp than eels. They are commonly known as “poraques”, in Brazil.
Image: A Peruvian electric eel was captured in Peru. This study has revealed that it is most likely to be E. varii .
Let me answer the second question briefly. It has been studied and it intrigues scientists. It will be discussed more later.
Here I will attempt to simplify what we know about the biological mechanisms that produce electricity in electric fish.
Let’s start with the basic biology of the animal.
The shock mechanism organs occupy most of your body. Other vital organs, which occupy less than one-fifth your body, are located directly behind your head 
The electrical part of the fish’s body is composed of three specialized organs: the main electrical organ (the Hunter organ) and the Sachs organ (the Sachs organ). Together, they make up 80 percent.  These cells, also known as electrocytes or small biological batteries, store electricity.
Their growth is responsible for an increase in their electrical discharge capacity. However, once they are adults, the charge stops growing and their final size is not proportional. 
However, it is still a mystery how these organs are used to produce electricity.
We must first understand the complexity of these electric organs.
The electric organs produce strong and weak electrical charges that are used for navigation, defense, hunting, communication, and communication. For this fish, stronger electric charges can cause exhaustion. The main electrical organ and two-thirds the Hunter’s Organ produce the strongest electric pulses. The weaker electric discharges are produced by the Sachs’ and Hunter’s organs. 
This is how an electric fish can charge the battery and use it for the purpose.
The electrical system of the eel provides it with a wireless Taser to stun its prey. Catania published a study last year that showed three types of electrical discharges by the eels: short, low-voltage pulses to sense their environment; high-voltage pulses while hunting; and high-voltage pulses during capture or defense. He demonstrated that the electrical pulses produced by the eel do not affect the muscles but the nerves controlling the prey’s muscle movements through a series of experiments. This causes strong, voluntary muscle contractions. 
It is rare in animal life, and basically acts as a remote control for the victim’s body. The load is sized according to the aggressor or victim so that energy doesn’t get wasted. (Let’s take a look at these fish!)
Image: The electric eel wraps its tail around its victim to increase the voltage of electrical pulses it receives. (Kenneth Catania / Vanderbilt University) 
How is it generated?
These discharges are caused by modified muscle cells, called electrocytes. The set of myoelectroplates is a collection of these special cells. A typical nerve cell produces an electrical potential of 0.14 volts.
An adult specimen may have 2,000 to 10,000 myoelectroplates depending on its size. They are organized in series like batteries in a flashlight. When the animal is excited, such as when it captures prey or defends itself, they activate their three electrical organs… simultaneously. 
The electric fish gets shocked, too!
The environment absorbs most of the expressive energy. It does not affect the person, as he has unique adaptations that allow him to channel it. 
How do electric fish find their prey in dark and muddy waters?
It’s not a good idea for fish to hide behind roots or underwater vegetation.
The eel also benefits from remote control capabilities by using doublets or triplets, which are short sequences of 2 to 3 milliseconds high-voltage pulses the eels emit while hunting.
As the eel glides along, it emits either a doublet, or a triplet. If there are fish nearby, the eel will emit a doublet or triplet. The spasm of the fish’s body will cause pressure waves to the water. The electric eels are able to detect water movement, even though they can’t see well. This tells the eel where its next meal is. 
Image: The eel’s electrical sensors are highlighted in red, while its water movement sensors have been highlighted in green. (Catania Lab / Vanderbilt) 
Fascinating, isn’t it? There’s more!
Biologists have known for a long time that electric fish and especially electric eels use low-voltage electric fields to navigate. Catania, in an article that was published online by Nature Communications Oct. 20, reported that electric eels have a secondary purpose for their high-voltage electrical systems: to track fast-moving prey. 
Image: The electric uses the electric impulses it generates not only to stun its prey but also as radar to locate their prey in dark and murky waters. (Kenneth Catania / Vanderbilt) 
It’s futile for the prey to try and escape once they are detected…
Catania demonstrated that the eels used feedback received from high-voltage volleys in order to pinpoint the prey’s position.
Catania stated that “the dual use of high-voltage systems as both a weapon, and as a sensor system shows that the eels’ hunting behaviour is far more sophisticated than we thought.” 
Everything is controlled by a complex central nervous system
The electric eel generates large electric currents by way of a highly specialized nervous system that has the capacity to synchronize the activity of disc-shaped, electricity-producing cells packed into a specialized electric organ. This is done by the nervous system through a command nucleus, which decides when an electric organ will turn on. A complex network of nerves ensures that thousands of cells are activated at once when the command is given.
Every electrogenic cell has a slightly lower than 100 millivolts of negative charge on its outside and its inside. The nerve terminal releases a brief puff of acetylcholine (a neurotransmitter) when the command signal arrives. This creates an electrical path that is very short and has low resistance. This creates a transient path with low electrical resistance connecting the inside and outside of one side of the cell.
The second question is the one that I’m returning to. Electric fish have been studied over the years and have contributed to greater knowledge of electricity. Electric eels are found in the Amazon basin. This has been known for 250 years. It was just that they didn’t know the number of species living in this area.  The photos here show three new species that were discovered recently.
Scientists used electric eels in 1799 to inspire the first battery design. They also have inspired ideas on how technology can be improved and treated for disease.
De Santana stated that the newly discovered electric eel species may have developed unique systems to generate electricity, which could make it easier to discover more.
He said, “It could have different enzymes or different compounds that could help in medicine or inspire new technology.” 
These studies are very recent, and electric fish continue to surprise us. These studies, however, are not new and have been around for quite some time.
Image: E. voltai was created in honor of Alessandro Volta, an Italian scientist who invented the first electric battery in 1799. He was partly inspired by the biology and ecology of electric eels .
Above, an E. voltai specimen was responsible for an unprecedented 860V discharge. This broke all records and earned it the title of “nature’s most electrified animal”. 
Hydrogel batteries): There are studies currently underway that mimic the operation of electric fish. They use an artificial organ to produce electrical energy using fresh water cells.