The fish crow was given its binomial name by the Scottish ornithologist Alexander Wilson in 1812, in the fifth volume of his American Ornithology.

The upperparts have a blue or blue-green sheen, while the underparts have a more greenish tint to the black.

More dramatically, when calling, fish crows tend to hunch and fluff their throat feathers.

Birders often distinguish the two species (in areas where their range overlaps) with the mnemonic aid "Just ask him if he is an American crow.

[16] Since 2012, fish crows have rapidly expanded into Canada, with breeding populations along Lake Ontario.

It feeds on small crustaceans, such as crabs and shrimps, other invertebrates, stranded fish, and live fish if the situation favors their capture, eggs and nestlings of birds, small reptiles, the fruits of many trees, peanuts, and grains, as well as human scraps where available.

[19] A pair of fish crows were reported to have raised a young blue jay for multiple weeks.

[19] This species appears to be somewhat more resistant to West Nile virus than the American crow.