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I Wish We Didn’t Know About the Heaviest Bony Fish Ever Found

A photo of an enormous dead sunfish, which is a strange-looking pale fish with triangle fins, hooked to a crane with a person examining the fish
Atlantic Naturalist

This week, seven years after a Boston man freaked out about what he perceived to be a "sea monstah" and five years after a Facebook user wrote an impassioned diatribe on Facebook explaining why their existence "truly is proof that God has abandoned us," the infamously large, misshapen sunfish, which resembles a winged pierogi, has gone viral once again.

The sunfish of our current moment is trending for being built like a tank—an impressive achievement considering how notably big every sunfish is. At 6,000 pounds, this particular southern sunfish, or Mola alexandrini, is believed to be the heaviest bony fish ever recorded. It was found near the Azores archipelago in December 2021 and documented in a study published this month in the Journal of Fish Biology. The previous record-holder, a female sunfish of the same species caught off Japan in 1996, weighed a paltry 5,070 pounds—nearly half a ton less than this new sunfish. One expert told Scientific American that fish get lighter after they die due to water loss, meaning these fish may have been even heavier alive.

Now, I love learning about creatures, be they new or old, big or small, record-breaking or extremely average. I loved learning about the bustling metropolis of parasites that dwell inside a sunfish—like the 60,000 to 100,000 internal parasites were found in a hoodwinker sunfish that washed up in Santa Barbara, or the nearly 10-foot-long, fettucine-shaped tapeworm recovered from another sunfish's intestine. But I am reluctant to celebrate having learned about the records smashed by a colossal sunfish that we only discovered because it was dead, possibly because we killed it.

a bird's eye view of the giant southern sunfish, with a human dwarfed by its body nearby
Atlantic Naturalist

The researchers encountered the sunfish as a carcass, floating near a harbor. Although the dissection found none of our human trash inside, the researchers noted a "large contusion" on the right side of the sunfish's head, an injury that could only have been caused by a large impact. The dissection also revealed traces of a brick-red antifouling paint on the sunfish's bruised skin, the kind of paint normally used on boat keels. Although it seems clear the sunfish was struck by a boat, the researchers said they could not determine whether the injury had occurred before or after the sunfish died.

Scientists do not know the lifespan of southern sunfish in the wild, but one of the authors of the new paper told The New York Times he believed the sunfish was at least two decades old. We will never know whether the sunfish was killed by a ship, something else entirely, or perhaps even passed from old age after living a long, full life. But it's worth noting that sunfish are hit regularly by boats. Mark Richards, the skipper of the supermaxi Wild Oats XI (this is word salad to me but I believe this means he races yachts in the ocean) hit three sunfish in 2005, which I learned in a story in The New York Times that was clearly sympathetic to the poor yachters who had to "retire their yachts from the race after such collisions." This story also mentions the unfortunate case of a "Reichel Pugh 51 named Secret Men’s Business" (this also apparently refers to a yacht) probably hitting a whale but still finishing the race, as if that anecdote is meant to be inspiring.

I didn't even know yacht racing was a thing before writing this story, but I now believe yacht racers are bad. How do I draw this conclusion? If I were racing a yacht simply because I was rich and wanted to go zoom-zoom in the ocean and I learned I hit a whale, I would regret it for the rest of my life and probably be haunted by the rightfully vengeful ghost of the whale I may have murdered. It takes a special (derogatory) kind of brain to hit a beautiful giant of the sea with your boat and then decide it's still worth it to keep going zoom-zoom, no matter how many dead whales and sharks and enormous sunfish lay in your wake. In this Fox Sports story about yacht racing, a skipper says "the course to Hobart is literally littered with sunfish." Littered? It's the freaking ocean! It's the sunfish's home, where you and your supermongo yacht Florence Pugh Corn Nuts XVIII are uninvited guests.

So again, we may never know if the southern sunfish found dead with a bump on its head in the Azores was killed by a boat or something else, or if it died of more natural causes only to be posthumously whacked in the noggin. But I do know that there are yacht races in the Azores. I am not drawing any conclusions, merely listing some facts.

An alive southern sunfish.
Erik van der Goot, CC by 4.0, via Wikimedia Commons

Although the researchers who examined the sunfish told news outlets they were sad to see the animal dead, they noted its discovery was "a hopeful sign" that the ocean can still support massive creatures, like fish the size of SUVs. This is true and good. I want everything in the ocean that wants to be big to get as big as it possibly can get. But I'm still going to be sad that a creature that started out as a 5-millimeter-long spiky baby resembling a literal sun and grew to be a beautiful 6,000-pound giant is now dead. I would rather have never learned about the humongous sunfish if it meant the fish would still be alive today, its head bumpy only in the places it should be, flapping gracefully beneath the waves, far from our sight.

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