fish louse

American  

noun

1. any of numerous small crustaceans, especially certain copepods, parasitic on the skin and gills of fish.

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fish louse British  

noun

1. any small flat rounded crustacean of the subclass Branchiura , having sucking mouth parts: parasites of fish

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Example Sentences

This superstition probably arose from the fact that a parasitic crustacean, known to watermen as "a fish louse," was often found clinging to the roof of the menhaden's mouth.

From Project Gutenberg