anal fin

American  

noun

1. the median, unpaired fin on the ventral margin between the anus and the caudal fin in fishes.

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anal fin British  

noun

1. a median ventral unpaired fin, situated between the anus and the tail fin in fishes, that helps to maintain stable equilibrium

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Example Sentences

For better distance, hook the bait through the anal fin and either let the bait settle at the bottom or flow in the current.

From Time Magazine Archive

Hook the head section of the mullet through both lips, and the tail portion just above the anal fin.

From Time Magazine Archive

I drew a dorsal fin on top and an anal fin on the bottom, to prevent the shark from rolling side to side when it was moving forward.

From "The Line Tender" by Kate Allen

The anal fin is long, with fourteen rays.

From Fishing in British Columbia With a Chapter on Tuna Fishing at Santa Catalina by Lambert, Thomas Wilson

Throughout the genus Callionymus,12 the male is generally much more brightly spotted than the female, and in several species, not only the dorsal, but the anal fin of the male is much elongated.

From The Descent of Man and Selection in Relation to Sex Volume II (1st Edition) by Darwin, Charles