O cardume tem uma espécie de peixe ornamental.

Because cardume is a masculine noun in Portuguese, so it takes o in the singular.

• o cardume = the school/shoal
• um cardume = a school/shoal

This is something you just have to learn with the noun, since grammatical gender in Portuguese does not always match any logical pattern.

Cardume is a collective noun that refers to a school/shoal of fish. It does not mean one fish. It refers to a group moving together.

So in grammar terms, it is singular, even though it refers to many fish:

• O cardume tem... = singular verb, because cardume is singular
• not O cardume têm...

This is similar to English words like group or team, which are singular in form but refer to multiple members.

Because the subject is o cardume, and cardume is grammatically singular.

• o cardume tem
• os cardumes têm

Even though a school contains many fish, Portuguese agrees the verb with the noun cardume, not with the individual fish inside it.

Yes. In Brazilian Portuguese, ter is very often used in everyday speech to mean both to have and there is/there are, depending on context.

Here, tem could suggest:

• the school has a certain species
• there is a certain species in the school

In formal writing, Portuguese may prefer há or existe/existem for there is/there are, but in normal Brazilian speech, tem is extremely common.

Because espécie is a feminine noun, so it takes uma.

• uma espécie
• a espécie

Even though the word ends in -e, it is feminine. That is another noun whose gender just has to be learned.

Uma espécie de means a species of, a kind of, or a type of, depending on context.

In this sentence, it introduces a classification:

• uma espécie de peixe ornamental = a species/type of ornamental fish

Be careful: in some contexts, uma espécie de can also mean something looser, like a sort of. For example, someone might say:

• É uma espécie de ritual. = It’s a kind of ritual.

So the phrase can be either scientific/classifying or more approximate, depending on context.

Because after expressions like espécie de, Portuguese often uses a generic noun without an article.

So:

• uma espécie de peixe ornamental = a species/type of ornamental fish

This sounds more like classification in general.

If you said:

• uma espécie de um peixe ornamental

that would usually sound unnatural in this context.

Portuguese often drops the article after tipo de, espécie de, qualidade de, etc. when talking about something as a category.

Because Portuguese often uses the singular after classification phrases like espécie de.

So:

• uma espécie de peixe ornamental

means a species/category whose members are ornamental fish.

This is similar to how English sometimes says a type of fish, not necessarily a type of fishes.

Using the singular here is the normal, natural choice.

In Portuguese, adjectives usually come after the noun.

So:

• peixe ornamental = ornamental fish

That is the normal word order. Putting the adjective before the noun is much less common and usually changes the tone or emphasis. With a technical/classifying adjective like ornamental, post-noun position is the standard one.

Yes, it is a very common combination. Peixe ornamental refers to fish kept mainly for display, beauty, or decoration, such as aquarium fish.

So this is not just any random noun + adjective combination; it is a normal category label.

Often, yes, but the nuance changes a little.

• uma espécie de peixe ornamental
• um tipo de peixe ornamental

Both can mean a kind/type of ornamental fish.

However:

• espécie can sound a bit more biological or taxonomic
• tipo is often broader and more everyday

In casual speech, tipo de is very common. If the context is scientific or biological, espécie de may be more precise.

In Brazilian Portuguese, espécie is pronounced roughly like es-PEH-see or es-PEH-shee, depending on accent and speed.

The important points are:

• the stress is on pé
• the written accent é shows the stressed syllable
• the final ie can sound compact in natural speech

A rough Brazilian pronunciation guide:

• espécie ≈ es-PEH-see

Not perfect, but helpful for an English speaker.

In Brazilian Portuguese, peixe is roughly pronounced PAY-shi.

A few details:

• pei- sounds like pay
• x here usually sounds like sh
• the final -e is often a light -i sound in Brazilian pronunciation

So a rough guide is:

• peixe ≈ PAY-shi

A rough Brazilian pronunciation is kar-DOO-mee.

The stress falls on du:

• car-DU-me

That final e is often pronounced like a light ee sound in Brazil.

Yes. This is a very useful thing to know.

Sometimes uma espécie de does not mean a literal biological species. It can mean:

• a sort of
• a kind of
• something like

For example:

• Ele inventou uma espécie de máquina. = He invented a kind of machine.
• Era uma espécie de festa. = It was a sort of party.

So the phrase can be exact or approximate. You understand which one is meant from context.

Probably this combination of three things:

1. Collective noun + singular verb

   • O cardume tem

2. Gender

   • o cardume because cardume is masculine
   • uma espécie because espécie is feminine

3. Classification structure

   • uma espécie de peixe ornamental
   • no article before peixe
   • peixe stays singular
   • adjective comes after the noun

So this sentence is a nice example of how Portuguese handles gender, agreement, and category expressions all at once.