Angry octopus caught punching big fish in South Pacific Ocean

Scientists were spying on ocean life in the South Pacific Ocean when their cameras caught something unusual: a fist fight.  

Researchers had dropped a baited remote underwater video system onto the seafloor at Morton Bank, around 75 miles off the coast of Rotuma (an island group around 400 miles north of Fiji). They were using the video to record the number of fish and marine animals in the area when they saw the fishy fracas. 

“We never really know what we’re going to see until we watch the footage back later,” says Chris Thompson, a marine ecologist at National Geographic Pristine Seas.

Despite always expecting the unexpected, the team was amazed to see a day octopus (Octopus cyanea) punching a highfin grouper (Epinephelus maculatus) before also going for – and narrowly missing – a spotcheek emperor (Lethrinus rubrioperculatus). Nat Geo Pristine Seas shared the footage on their Instagram. 

“There are a few theories as to why octopus might punch fish,” says Thompson. “They may be displacing fish to gain access to prey or exerting discipline in a collaborative partnership to spite… or just because.”

This isn’t the first time an octopus has been seen punching fish – a 2020 study in Ecology describes the same species of octopus lashing out while hunting with fish in the Red Sea, suggesting the thwack might be a way of keeping the group in line. 

“With their different skills, working together likely increases the chances of each party finding and capturing prey,” says Thompson. But, if the fish aren’t pulling their weight, the octopus might get physical. 

Landing a punch could be “a way of disciplining the fish into participating actively in the hunt rather than exploiting it and freeloading off the octopus and other fishes’ work,” he says. “So, it’s possible that in this video the octopus is keeping the grouper on task.”

Rotuma is nearly 1,000 miles away from the Red Sea but there are clearly similarities when it comes to its inhabitants. “That we are seeing this same behaviour in a remote location on the other side of the planet (over 15,000 km away) shows that these octopuses are up for a bit of biff wherever in the world they are,” he says.  

Image and video credit: National Geographic Pristine Seas

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