This article is produced in collaboration between the Echo editorial board and our partners at the Clio History Journal. For more of their articles, click here.

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Edited by Hailey Strom

      As of 2022, humanity has discovered a measly five percent of the ocean. Because of this, new discoveries regarding marine life and the ocean’s ecosystem are being made on a near-daily basis. One of the most recent and popularized of these fantastical discoveries was that of a fish with a transparent head.

     Named the barrel-eye fish, Macropinna microstoma, or the “spook-fish,” resides in the deep sea between the waters of the Bering Strait of Japan and Baja California. Researchers there had to go up to 2,600 feet, or 800 meters, below the surface to get a good look at the bright-eyed fish.

     In such deep waters, with little light and warmth, the main food source this fish has is zooplankton. When scientists were able to look into the fish’s stomach, they also saw tentacles of siphonophores, which are colonies of zooids that divide into identical copies of themselves to perform specific functions as a free-floating colony similar in appearance to jellyfish. The tentacles of the siphonophores held zooplankton and crustaceans that then got sucked up by the barrel-eye fish.

     The spook-fish has a transparent head that does not conceal any of its organs; however, this is not what it has become famous for. Its claim to fame is its eyes. The spook-fish has bright green eyes that point directly upward.

     This fascinating find is thanks to the Monterey Bay Aquarium Research Institute. The evolutionary purpose for these eerie eyes is so that the fish is able to spot any potential predators or prey nearby in the dark water. The green color of the eyes helps the fish see what remains of the surface sunlight and to see the bioluminescence in other sea life like jellyfish. The rest of the head is filled with fluid, and it is inferred by the institute that it will protect the fish’s eyes from any attacks while feeding.

     The body of the barrel-eye consists of large flat fins, which help the fish move in certain ways while it is almost still in the water. This species of fish is small, approximately six inches, or fifteen centimeters, long, and the body is brown in color.

     Bruce Robison, the head researcher for the project, is a deep-sea biologist at the Monterey Bay Aquarium Research Institute. Robinson has been researching the barrel-eye for about 30 years, with nearly 5,600 dives under his belt, solely dedicated to looking for the fish. He states that in his thirty years of research, he and his team have only seen the fish alive about eight times, “We do spend a lot of time exploring down there, so I can say with some confidence that they’re quite rare,” he says.

     The way that the team was able to see and study the fish alive was to have it brought to the surface by a net and remotely operated vehicles that are specifically designed for deep-sea diving. The fish only stayed alive for a few hours, and it is from this short time that most knowledge of the fish is derived.

     Yet, just those few hours were enough for Robison to make significant gains regarding the knowledge of this fish. Robinson even comments on the fish’s overall appearance, stating he always thought the way the fish’s eyes aimed upward was puzzling.

     The barrel-eye fish is still a new discovery for deep-sea scientists like Bruce Robison. There has been little contact with the fish over the years, so it is hard to answer the more important questions: how long they can live, why their heads are transparent but not their bodies, and how to clearly discern the fish’s mating habits.

     Since the spook-fish doesn’t come out from below the sea, it makes it hard for researchers to even study deeper into the fish’s anatomy itself when alive, but the progress they have recently made has been significant and should not be understated.

Real life photos of the bizarre barrel-eye fish can be found at the Monterey Bay Aquarium Research Institute’s website.

 References 

 “Discovered in the Deep: The Incredible Fish with a Transparent Head.” The Guardian, Guardian News and Media, August 31, 2022, www.theguardian.com/environment/2022/aug/31/barreleye-the-incredible-fish-with-a-transparent-head.

 Jordan, Rain. “Take A Look Inside the Barreleye Fish: The Marine Animal With a Transparent Skull.” Nature World News, 1 Sept. 2022, www.natureworldnews.com/articles/52866/20220901/take-a-look-inside-the-barreleye-fish-the-marine-animal-with-a-transparent-skull.htm.

Montereybayaquarium.org, www.montereybayaquarium.org/animals/animals-a-to-z/barreleye.

 “Sea Wonder: Barreleye.” National Marine Sanctuary Foundation, http://marinesanctuary.org/blog/sea-wonder-barreleye/ (accessed January 26, 2022).