Electric fish are a rare but intriguing phenomenon. In their usual habitat where light is scarce, most use their unique power for navigation and communication. Yet some rare species harness this ability in hunting. But how do electric fish produce an electrical current and how do they use it for their advantage?
Every electric fish possesses electric organs that produce electricity. The fish’s brain sends a signal through its nervous system to the electric organ. The organ is filled with hundreds of thousands of disk-shaped cells called electrocytes. Electrocytes pump out sodium and potassium ions maintaining a positive charge outside and negative charge inside.
When nerve signals arrive at the organ, they cause the ion gates to open. The positives ions flow back in creating a negative charge on the on the outside of the electrocytes creating a current. As the nerves arrive at the same time, the electrotypes act like thousands of batteries in series.
The ways fish harness this ability varies. The nearly 350 types of electrical fish are divided into two sections, strongly electrical and weakly electrical fish.
As the name suggests, weakly electrical fish produce a weak current that is typically up to one volt. The electric organ in their body is located near their tail. This means that they are unable to create a current strong enough to paralyze their prey. Instead, they use this ability to communicate and detect shapes and sizes of nearby objects.
On the other hand, strongly electric fish possess the ability to shock and attack its prey, the strongest being the electric eel. It possesses 3 electric organs placed through most of its long body. It attacks its prey through first emitting 2 or 3 strong pulses with a charge of almost 600 volts, sending its preys muscles into tremors. Next, numerous high voltage discharges contract its muscles further. This electrical attack eventually immobilises its prey, allowing the electrical eel to consume it.
An unknown fact about the animals remains; why do they not electrocute themselves? Although scientists have learnt more about this phenomenon, creating hypothesis and theories on why it is so, this mystery remains unanswered.