Ryby żyją w wodzie.

Ryby is the plural form of ryba meaning fish.

• ryba = a fish / the fish (singular)
• ryby = fish (plural)

In this sentence, ryby is the subject, so it means fish as a group.

A useful extra point: ryby can also be the accusative plural form, but here it is clearly nominative plural because it is the subject of the sentence.

Żyją is the 3rd person plural present tense form of the verb żyć, which means to live.

So:

• żyć = to live
• żyją = they live

Because ryby is plural, the verb also has to be plural:

• Ryba żyje = A fish lives
• Ryby żyją = Fish live

Żyją is:

• 3rd person
• plural
• present tense

In English, that corresponds to they live.

Polish verbs often show the subject through their endings, so the ending -ą here tells you it is they.

Because after the preposition w meaning in, Polish usually uses the locative case when talking about location.

So:

• dictionary form: woda = water
• locative form: w wodzie = in water

This is very common in Polish:

• w domu = in the house
• w szkole = at school / in the school
• w wodzie = in water

So woda changes to wodzie because the grammar requires it.

Wodzie is the locative singular form of woda.

The pattern is:

• woda = nominative singular
• wodzie = locative singular

After w when it means in, Polish normally uses the locative:

• w mieście = in the city
• w Polsce = in Poland
• w wodzie = in water

Polish does not have articles like English a, an, and the.

So ryby can mean simply fish, and the exact sense depends on context.

Likewise, wodzie does not need an article either. English forces you to choose things like in the water or in water, but Polish often leaves that unspecified unless the context makes it clear.

That is why Ryby żyją w wodzie can naturally express a general truth.

Yes. This sentence is a general statement about fish as a type of animal.

Polish often uses the plural this way to talk about a whole class of things:

• Psy lubią biegać. = Dogs like to run.
• Ptaki latają. = Birds fly.
• Ryby żyją w wodzie. = Fish live in water.

So this is not necessarily about some specific fish. It is a general fact.

Yes, Polish word order is more flexible than English because the grammar is shown partly through word endings.

The neutral order here is:

• Ryby żyją w wodzie.

But other orders are possible, for example:

• W wodzie żyją ryby.
• Żyją ryby w wodzie.

These alternatives may sound more marked, poetic, or context-dependent. The original order is the most straightforward and natural for a basic statement.

No. In Polish, subject pronouns are often omitted because the verb ending already tells you the person and number.

So:

• żyją already means they live

You could say:

• One żyją w wodzie

but that is usually unnecessary and often unnatural unless you want special emphasis or contrast. Normally, just Ryby żyją w wodzie is enough.

A rough English-friendly guide is:

• żyją ≈ ZHIH-yohng

A few important points:

• ż sounds like the s in measure
• y is a short Polish vowel with no exact English match
• ją is nasalized; the final ą is not exactly like a normal English vowel

Also:

• ży is not the same as ji
• ją is not pronounced exactly like English yon, though that approximation can help at first

If you are learning pronunciation, it is worth listening to native audio because Polish nasal vowels like ą are hard to master from spelling alone.

Yes, żyć is the natural verb here because it means to live in the broad sense.

So:

• Ryby żyją w wodzie = Fish live in water

You might also learn mieszkać = to live/reside, but that is more like to live somewhere as your place of residence.

For animals in a general biological sense, żyć is the better choice here.

Compare:

• Mieszkam w Warszawie. = I live in Warsaw.
• Ryby żyją w wodzie. = Fish live in water.

The singular version is:

• Ryba żyje w wodzie.

This means:

• A fish lives in water
• or The fish lives in water, depending on context

Notice the changes:

• ryby → ryba
• żyją → żyje

But w wodzie stays the same, because woda is still singular and still follows w with the locative case.