Аквариумный компрессор работает тихо.

Аквариумный компрессор means aquarium compressor / aquarium air pump using an adjective + noun pattern, which is very common in Russian.

• аквариумный = aquarium-related
• компрессор = compressor / pump

So the phrase literally means an aquarium-type compressor or a compressor for an aquarium.

You could sometimes express similar ideas with a noun in the genitive, but with product types or categories, Russian often prefers an adjective:

• аквариумный компрессор = an aquarium compressor
• compare English aquarium pump

This sounds natural and standard.

Аквариумный is an adjective meaning for an aquarium, aquarium-related, or used with aquariums.

It comes from аквариум (aquarium) plus the adjective ending -ный.

So:

• аквариум = aquarium
• аквариумный = aquarium / aquarium-related

In this sentence, it tells you what kind of compressor it is.

Because it agrees with компрессор.

Russian adjectives change their endings to match the noun in:

• gender
• number
• case

Here:

• компрессор is masculine
• singular
• nominative case (because it is the subject)

So the adjective must also be masculine singular nominative:

• аквариумный компрессор

If the noun changed, the adjective would change too.

It is in the nominative case.

That is because it is the subject of the sentence — the thing performing the action.

The sentence structure is:

• Аквариумный компрессор = subject
• работает = verb
• тихо = adverb

So the basic meaning is: The aquarium compressor works quietly.

Работает is the 3rd person singular form of работать.

It can mean:

• works
• is working
• operates
• runs

In this sentence, the most natural English translation is something like:

• works quietly
• runs quietly
• operates quietly

For machines, работать is very commonly used.

The dictionary form is работать (to work).

Russian verbs normally lose the -ть infinitive ending when they are conjugated.

Here the subject is singular:

• компрессор = it

So you need the he/she/it form:

• работать → работает

This is the normal present-tense form for he/she/it works.

Because тихо is an adverb, while тихий is an adjective.

• тихий = quiet (describes a noun)
• тихо = quietly / in a quiet way (describes a verb or the manner of an action)

Here, тихо describes how the compressor works:

• работает тихо = works quietly

If you said тихий, you would be describing a noun, not the action.

It can mean either, depending on context.

In this sentence, тихо most naturally means:

• quietly
• with little noise

So Аквариумный компрессор работает тихо suggests the machine is not loud.

For machines, this is a very natural choice.

Not literally, but it is very close in meaning.

The Russian sentence specifically says:

• The aquarium compressor works/runs quietly

So it focuses on how it operates, not directly on its permanent quality.

Still, in real-life context, English speakers might translate it more freely as:

• The aquarium compressor is quiet

That would often communicate the same practical idea.

No, Russian word order is fairly flexible.

The neutral order here is:

• Аквариумный компрессор работает тихо.

This is the most straightforward way to say it.

But other orders are possible for emphasis, for example:

• Тихо работает аквариумный компрессор.
• Аквариумный компрессор тихо работает.

These can sound slightly more marked or stylistic depending on context. For a learner, the given order is the best default.

Russian has no articles.

So:

• компрессор can mean a compressor or the compressor
• the exact meaning depends on context

That is completely normal in Russian. English requires articles; Russian does not.

Yes. In Russian, компрессор is commonly used for the device that pumps air into an aquarium.

Depending on context or region, English may say:

• air pump
• aquarium pump
• compressor

So even if compressor sounds a bit technical in English, it is a normal Russian word here.

The simplest negation is:

• Аквариумный компрессор не работает. = The aquarium compressor is not working.

If you want to negate quietly, you could say:

• Аквариумный компрессор работает не тихо. = The aquarium compressor does not work quietly.

But that sounds a bit less natural in many situations. Often Russian would instead use a more direct opposite, such as:

• Аквариумный компрессор работает громко. = The aquarium compressor works loudly.

The pattern is:

[subject] + [verb] + [adverb]

So:

• Аквариумный компрессор = subject
• работает = verb
• тихо = adverb

This is a very common and useful Russian sentence structure:

• Мотор работает хорошо. = The motor works well.
• Телевизор работает нормально. = The TV works normally.
• Вентилятор работает тихо. = The fan runs quietly.

So this sentence is a good model to remember.