mad as a fish

In real, traceable use. Part of the curated seed collection; community review is coming.

Meaning · English

Demented, crazy.

Register: slang

Where it’s used: Used American English

Examples

Voluble, almost incomprehensible, mad as a fish and perpetually drunk.

Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30)

Sources & notes

Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).

Common questions

What does “mad as a fish” mean?

Demented, crazy.

Is “mad as a fish” formal or informal?

mad as a fish is generally slang.