Preeti Desai found the decaying fish on a beach in Texas City, and asked Twitter for help.
She posted several photos with the caption: "Okay, biology twitter, what the heck is this?"
Her request was passed to biologist and eel specialist Dr Kenneth Tighe, who believes it is a fangtooth snake-eel.
He said it may also be a garden or conger eel, because "all three of these species occur off Texas and have large fang-like teeth".
It is thought that Hurricane Harvey, which brought strong winds and flooding to Texas, could explain why the creature was washed up.