Rattail fish

Food is scarce in the deep sea and, without sunlight, can be hard to find. But those big blue eyes give the rattail an edge. It can glimpse even the faintest flickers of bioluminescence—the “living light” produced by deep-sea animals. Keen eyesight reveals prey, like fishes and squid, darting in the waters above the seafloor.

A rattail relies on other senses, like smell and touch, to find a meal too. It has a nose for rotting carrion, and sensitive barbels on its chin detect small crustaceans or worms wiggling in the mud below.

Humans play a pivotal role in deep-sea food webs too. As fish stocks in the ocean’s sunlit shallows dwindle, fisheries cast their nets to deeper waters. You might see “grenadier” as the catch of the day in restaurants and seafood markets—that’s a deep-sea rattail fish sold under a more palatable market name. Rattails and other deep-sea fishes grow slowly and mature late in life, making them vulnerable to overfishing. The gear used to catch these fishes may harm seafloor habitats or unintentionally catch other species too. Thankfully, effective management for rattail fisheries on the West Coast has reduced the risk of overfishing and habitat damage. The Monterey Bay Aquarium’s Seafood Watch guide can help you make seafood selections that keep ocean health in mind.

Fast Facts

• Maximum Size: 1 meter (3.2 feet)
• Depth: 200–4,000 meters (600–13,100 feet)
• Habitat: seafloor
• Range: worldwide
• Diet: fishes, invertebrates, and scavenged carrion

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