A bizarre video supposedly showing two "monster fish" passing an eel from one's mouth to the other was widely circulated on social media in the spring of 2021. Viewers be warned, the following video is weird, possibly disturbing, and just all around gross.
This video does not showcase a natural occurrence. There is no species of fish that we are aware of that lives in the sand and occasionally regurgitates eels for its monster fish buddies to eat.
This video comes from the India-based YouTube channel Discovery Site. The original video is entitled "Underground Monster hunting eelfish. Big fish swallowing mudeel. Big fish vomiting eel to big fish."
This channel is replete with similarly absurd videos that showcase various "fishing techniques," and other seemingly odd fish behaviors. In another video, for example, a group of land-dwelling fish emerge from their holes to visit a watering hole. In another video, raw egg is used to coax "climbing perch" out of their holes.
These videos do not document genuine natural occurrences. These are all staged videos that seemingly use dead fish as their main props. Many of these videos are accompanied with a disclaimer, stating that these videos are for "entertainment purposes only" and do not reflect reality.
While these videos may be bizarre, they are undoubtedly popular.
Since its inception in August 2020, the Discovery Site YouTube page has racked up more than 100 million views. And the Discovery Site is not the only YouTube channel that makes these oddly staged fish videos. Fisherman Animal Lover is another page (with more than 1 million subscribers) that creates similar content. A since-deleted YouTube page called Technique Tools scored a viral hit back in 2019 with a video supposedly showing fish being driven out of a hole with Coca-Cola and Mentos. This video, too, was just a hoax.
In short, the video of "monster fish" exchanging an eel meal is a staged piece of footage that most likely uses dead animals.