This is probably a gempylid fish, judging from the large caudal fin I have seen on some additional images.

However, for generic and species identification we would need to know the number of dorsal fin spines and soft rays, anal fin rays, the position of the anus relative to the beginning of the anal fin, shape of scales, shape of the keel on the caudal peduncle, etc.

Promethichthys prometheus (Cuvier, 1832)

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