Nearly 350 species of fish have specialized anatomical structures that generate and detect electrical signals. Underwater, where light is scarce, electrical signals offer ways to communicate, navigate, find, and sometimes stun prey. But how do these fishproduce electricity? And why? Eleanor Nelsen illuminates the science behind electric fish.

1. How do fish make electricity? - Eleanor Nelsen
https://youtu.be/z0M7_HPSi14
Nearly 350 species of fish have specialized anatomical structures that generate and
detect electrical signals. Underwater, where light is scarce, electrical signals offer
ways to communicate, navigate, find, and sometimes stun prey. But how do these
fishproduce electricity? And why? Eleanor Nelsen illuminates the science behind
electric
fish.
1.- Which of these species is classified as a strongly electric fish?
APeters' elephantnose fish
BAnglerfish
CElectric catfish
DBlack ghost knifefish
2.- Electric fish use specialized cells to produce electricity. What are these called?
ACnidocytes
BBattery cells
CSachs' organ
DElectrocytes
3.- How many electric organs do electric eels have?
A3
B5
C2
D1
4.- Which of these is not possible for weakly electric fish?
AUsing electrical signals to communicate

2. BUsing electrical signals to navigate
CFinding hidden prey
DImmobilizing their prey
5.- How do the pulses generated by an electric eel affect its prey?
ADestroy nerve endings
BCause muscle contractions
COverstimulate the retina, causing blindness
DCreate lesions on the brain stem
6.- Explain, step by step, how an electrical current is generated in the electrocytes.
7.- What is one way the electric eel can increase the intensity of the electric charge
it delivers to its prey?
8.- What is the function of the schnauzenorgan in the Peters' elephantnose fish?
Vanderbilt professor and electric-eel expert Ken Catania was curious to see if he
could confirm von Humboldt’s account of the leaping eels, so he set out to replicate
the experiment. He determined that electric eels would, in fact, throw themselves
out of the water to attack a perceived threat, suggesting that Humboldt’s story
was likely true. Catania even got video footage of an eel leaping at a fake human
arm. You can also read more on Catania’s work demonstrating that electric
eels “remote-control” their prey.
Electrocytes are modified muscle. Scientists at the University of Wisconsin
have studied the genetics behind the transition from muscle cells to electricity-
producing cells, and discovered that this remarkable ability evolved six different
times.
Centuries before the invention of anesthesia or modern painkillers, physicians who
happened to live near the habitats of strongly electric fish employed their shocks
as analgesia. The Romans used the electric torpedo ray to treat headaches and
gout, and the Greeks used them during childbirth (in fact, the English word
“narcotic” is derived from narke, the Greek word for these rays).

3. DISCUSS
There’s much less light in underwater environments. Electric signals provide a way for
fish to communicate, navigate, and hunt. What are some other strategies that might
be useful in dim light?