Handling High Voltage

It wasn't until 2019 that scientists discovered there are three different species of electric eel; for 250 years, it was believed there was only one. One of the newly discovered species, Electrophorus voltai, can produce an astounding 860 volts of electricity—the highest level of electricity generated by any animal on Earth.

The species of electric eel in our care at the National Aquarium—Electrophorus electricus—isn't quite as electrifying, but its shock still packs a powerful punch, clocking in at a maximum of 600 volts. This high voltage is deployed to protect them from predators or to stun and kill prey. More often, they emit lower-level electrical pulses to help them navigate and explore the muddy waters in which they live.

The majority of an electric eel's body is comprised of its tail, where its electricity-generating muscles are found. Its vital organs are found in just one-fifth of its body and are located directly behind its head.

Recently, a new electric eel was added to the Shocking habitat in Surviving Through Adaptation. Before it was cleared to be added to the exhibit, it had to undergo a routine medical exam at the end of its quarantine period at our Animal Care and Rescue Center. As is the case anytime an electrical eel in our care is handled for an exam, a few extra precautions were put in place to avoid any unwanted zaps from this electrifying animal and keep our Animal Health team safe.

Most animals are anesthetized for their quarantine exams to allow for greater ease when collecting samples and to decrease stress on the animal. In the case of electric eels, this is even more important from a safety perspective. During the recent exam, powdered anesthetic was dissolved into the water and the electric eel began to feel its effects, it began discharging bursts of electricity. This was an important step in the process; once the eel had finished discharging, the anesthesia made it difficult for it to produce high levels of electricity while it was sedated.

Our team worked quickly to perform the exam—which included a blood draw, gill check, cloacal flush, skin scrape, ultrasound and radiographs—so that the animal could be sedated for the shortest amount of time possible. The team used a tool called a voltmeter to keep an eye on the voltage being emitted by the eel for the duration of the exam. The probe of the meter was kept in the water at all times and a staff member was checking the reading roughly every five to 10 minutes.

Since the electric eel was under anesthesia, it didn't have the physical bandwidth to fully recharge and emit high voltage impulses. Although the voltage it was emitting was lower than it would typically be, it never went down to zero since its muscles naturally still give off electrical impulses, even while sedated. Staff monitored the voltmeter for readings exceeding a target of 20 volts; water can conduct electricity, so this safety threshold was set to minimize any potential for harm to the team handling the eel.

Despite its name, the electric eel isn't an eel at all; it's a species of knifefish in the order Gymnotiformes, which contains over 250 species of electric fishes. True eels do not generate electricity.

Animal Health experts who physically handled the eel also had to wear long rubber gloves, an additional precaution to keep our staff safe. Rubber is an insulator material, which means that it does not allow electric current to conduct easily, so wearing these gloves is a protective measure against any electricity the eel was producing.

The exam was a success: The electric eel passed with flying colors, meaning it was healthy and ready to be put on exhibit, and thanks to the diligence of our staff, it was a shock-free experience.