Estar pez

to know nothing about...; **to know nothing about...**; **to be clueless about...**; **to be completely lost**; **to be at sea** (especially when confused); **to have no idea**

Estar pez means to know very little or nothing about a particular subject.

It often suggests complete unfamiliarity rather than lack of intelligence.

Someone may be an expert in one area and estar pez in another.

• knows nothing about a topic
• is completely lost in a conversation
• has not studied for an exam
• lacks the necessary knowledge
• admits their own ignorance

It works by plain analogy with a scene anyone can picture.

Several theories exist.

One suggests that fish were traditionally associated with silence and apparent lack of understanding.

Another links the expression to the image of someone moving helplessly outside their natural environment.

No explanation has been universally accepted.

What is certain is that the expression has been firmly established in Spanish for generations.

Spanish speakers very often use the expression about themselves:

Estoy pez en economía.

This sounds much more natural than simply saying:

No sé mucho de economía.

The expression is usually self-deprecating rather than insulting.

Spanish has many very short idioms that replace much longer explanations:

• Estar pez → to know nothing about something.
• Estar verde → to be inexperienced or not yet ready.
• Estar frito → to be exhausted or in serious trouble (depending on context).

These tiny expressions are among the hardest for advanced learners because their meanings cannot be guessed from the individual words.

Do not translate the expression literally.

English speakers would never say:

I'm a fish at mathematics.

Instead, use expressions such as:

• I'm clueless about maths.
• I know nothing about maths.
• I'm completely lost when it comes to maths.

The emphasis is on lack of knowledge.