Watch: Eel Swallows a Pufferfish Whole
Approaching slowly, the moray eyes the puffer, pauses to assess its target, and then suddenly springs into action, grasping the unsuspecting pufferfish in its jaws. Attempting to escape, the pufferfish inflates to nearly twice its size.
While the eel initially appears to struggle to keep its jaws clamped around the inflated fish, it eventually succeeds in crushing it like a balloon before seemingly swallowing it whole.
The battle was captured by diver Vital Bazarov, who was on a recreational dive with friends when he stumbled upon the incident.
Both fish employ drastically different, yet effective, methods of defense and attack.
When threatened, pufferfish inhale large amounts of water into their abdomen. Their inflated bodies make it difficult for eels to maintain their grip, allowing the fish to escape.
Eels, on the other hand, take a more aggressive approach to ensnaring their prey. They have a second set of teeth, pharyngeal jaws, that allow them to simultaneously grab prey while sucking it further into their mouth. Eels are the only known vertebrae with this adaptation.
Holly Bourbon, the director of dive programs at the National Aquarium, explains this second jaw is an essential tool for eels to secure their catch.
"Eels will also tie themselves in a knot and then untie as that action will help create a back pressure to help ingest prey," explained Bourbon.
(Watch a puffer fish escape from the jaws of an eel.)
Puffing up their bodies isn't the only method of defense used by pufferfish. Some are also highly toxic.
It's possible that by successfully grasping and eating a pufferfish, this moray eel's meal will be its last. Pufferfish toxins are synthesized from bacteria in the animals they eat and are contained in their liver and gonads. Whether or not an eel survives its pufferfish dinner varies by the pufferfish's species, geographic region, and time of year.
In Japan, pufferfish are a delicacy called fugu, but one incorrectly prepared piece of fish is capable of killing a person. Tetrodotoxin, found in some pufferfish species, is a thousand times more deadly to humans than cyanide.
The toxin they contain is known as tetrodotoxin, which causes damage to the nervous system. Currently there is no known antidote.