La pescadera me recomendó unas gambas y unos mejillones muy frescos.

Pescadera is the feminine form of pescadero and means female fishmonger or woman who sells fish.

• el pescadero = the male fishmonger
• la pescadera = the female fishmonger

In this sentence, the speaker is talking about a specific woman, so la means the.

Me means to me.

So:

• recomendó = recommended
• me recomendó = recommended to me

Spanish often uses an indirect object pronoun where English may just use word order:

• La pescadera me recomendó... = The fishmonger recommended ... to me

Other forms would be:

• te recomendó = recommended to you
• le recomendó = recommended to him/her
• nos recomendó = recommended to us

Recomendó is the third-person singular preterite form of recomendar.

• yo recomendé = I recommended
• tú recomendaste = you recommended
• él/ella/usted recomendó = he/she/you recommended

The accent matters because it shows both pronunciation and verb form.

Compare:

• recomendo = not a correct standard form here
• recomendó = he/she recommended

So La pescadera me recomendó... means The fishmonger recommended...

Because the speaker is talking about some prawns and some mussels, not just one prawn or one mussel.

Singular:

• una gamba = a prawn
• un mejillón = a mussel

Plural:

• unas gambas = some prawns
• unos mejillones = some mussels

In real-life shopping or restaurant situations, Spanish often uses the plural for foods like this because people usually buy or order more than one.

Because the articles must agree with the noun in gender and number.

• gamba is feminine singular → una gamba

• gambas is feminine plural → unas gambas

• mejillón is masculine singular → un mejillón
• mejillones is masculine plural → unos mejillones

Here, unas/unos often means some rather than emphasizing the exact number.

Great question. Frescos describes both nouns together: gambas and mejillones.

When Spanish uses one adjective for a mixed-gender group, the adjective normally becomes masculine plural.

So:

• unas gambas muy frescas = some very fresh prawns
• unos mejillones muy frescos = some very fresh mussels
• unas gambas y unos mejillones muy frescos = some very fresh prawns and mussels

Because the group includes a masculine noun (mejillones), the combined adjective is frescos.

Not in this exact sentence if muy frescos is describing both the prawns and the mussels together.

• muy frescos = correct for the mixed group
• muy frescas would only work if the adjective referred just to gambas

For example:

• La pescadera me recomendó unas gambas muy frescas.
  Here frescas matches gambas only.

But once you add unos mejillones and use one adjective for both, Spanish normally switches to masculine plural: frescos.

Because in Spanish, descriptive adjectives often come after the noun.

So:

• gambas frescas = fresh prawns
• mejillones frescos = fresh mussels

Adding muy gives:

• muy frescos = very fresh

This is the normal order in Spanish. English usually says very fresh mussels, but Spanish commonly says mejillones muy frescos.

In Spain, gambas usually means prawns or sometimes shrimp, depending on context and translation choice.

A few useful notes:

• In Spain, gamba is a very common seafood word.
• In English, the exact translation may vary between prawn and shrimp.
• In many learning materials for Spain Spanish, gamba is often translated as prawn.

So if you are learning Spanish from Spain, prawns is usually a good choice.

Because gambas and mejillones are things, not people.

The personal a in Spanish is usually used before a specific person (or sometimes a pet/personified being) when that person is the direct object.

Compare:

• Vi a María. = I saw María.
• Compré mejillones. = I bought mussels.

In this sentence, the fishmonger recommended seafood items, so no personal a is needed.

Yes, that is possible, but it changes the feel slightly.

• unas gambas y unos mejillones = some prawns and some mussels
• gambas y mejillones = a more general or less specifically packaged mention of prawns and mussels

Using unos/unas makes the sentence sound a bit more natural in many everyday buying situations, as if the fishmonger recommended some particular prawns and some particular mussels.

It can be translated as either, depending on context.

• recomendar often means to recommend
• In a shop or market context, it can also feel like to suggest

So this sentence could naturally mean:

• The fishmonger recommended some very fresh prawns and mussels to me.
• The fishmonger suggested some very fresh prawns and mussels.

Both are good English interpretations.

They are:

• gamba → gambas
• mejillón → mejillones

Notice the accent change:

• mejillón has an accent in the singular
• mejillones loses the accent in the plural

This is because Spanish accent marks depend on the word’s stress pattern.