fish knife

noun

a small knife with a spatulalike blade, used with a fork in cutting fish at table.

Origin of fish knife

1375–1425; late Middle English fishknif

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

But if you will have the truth: the fish-knife business by all means.
At The Sign Of The Eagle
Gilbert Parker
"I should say five, poppa," exclaimed Miss Chrysie, putting her fish-knife down somewhat sharply on her plate.
The World Masters
George Griffith
On Lil's silken bosom reposed a diamond-and-platinum pin the size and general contour of a fish-knife.
Half Portions
Edna Ferber