Green’s Dictionary of Slang

fish v.1

[? SE fish for compliments]

1. [late 18C+] (US campus) to toady, to ingratiate oneself.

2. [late 19C] to interrogate.

SE in slang uses

In phrases

fish for food (v.) [food n. (1)]

[1940s] (US black) to gossip.

fish or cut bait

[mid-19C+] either carry out what you’re doing to the fullest extent or let someone else more competent get on with it while you take a secondary role

fish (out) (v.) (also fish up)

1. [late 19C+] to obtain, to produce.

2. [1930s] (US Und.) to rob.