The phrase is casual and might be considered disrespectful if used in formal situations.

Informal Usage

While it points out someone's unusual traits, it doesn't necessarily mean it's bad to be an odd fish.

Not Negative

The phrase could be cultural as some societies celebrate odd fish more than others.

The term queer fish often shows the speaker is puzzled by someone's unpredictable behavior.

Calling someone a queer fish doesn't have to be personal; it can refer to their actions, not their character.

The phrase can be used to start a conversation about someone's interesting qualities.