Nope, we don't say "pesci vivono in acqua" but pay attention: for us (Italian people) the word "pesci" is plural and countable, while in English is uncountable and the verb "live" is required. Anyway, the Duo translation is not good, if not wrong ...I am studying English language, by the way... I'm Italian
in english 'fish' can be plural and countable. it can also be singular and countable. it isn't an abstract idea nor a liquid or powder, nor cut up pieces of (which aren't alive). because it lacks an 's' or 'es' doesn't make it uncountable. that isn't the test. the verb 'live is only required when you are talking about multiple fish. 'a fish lives..." "the fish live/lives..." here is a page on usage. https://en.wiktionary.org/wiki/fish
there is another equivalent countable word in English--'fishes'.
'in acqua' is used in some expressions such as 'in acqua fino alle ginocchie' 'knee deep in water', 'in acqua cattiva' 'in deep water' (in trouble). I think I have seen 'in acqua' in a post on the performance of a boat performance hydrodynamically. I don't remember the quote.
100% correct. This ambiguity exists and you can remove it by using something like "quel/quello/quella/quei/quelle" (those). Normally, however, the context suffices. So in summary I can think of:
- I pesci vivono nell'acqua => [The] fish live in [the] water
- Quei pesci vivono nell'acqua => The fish live in [the] water
- Quei pesci vivono in quell'acqua => The fish live in the water
I am just guessing, but I think in Italian you cannot express this distinction.
"Fish live in water" is a general statement about the species 'fish'.
When we say "The fish live in the water", we are talking about specific fish which we have talked about before or which we have seen before. The same way "the water" refers to water we have already talked about or that we have seen.
However, I find it strange to have "the" both in front of fish and in front of water.
No, not so based upon how Duolingo chose to translate the sentence. "The" completely changes the meaning of the sentence in English from a general statement that all fish live in water to the fish we are talking about live in water. Adding "are" also changes the meaning in English from fish in general live in water, as opposed to living somewhere else, to fish are indeed living in the water, as opposed to there are no fish in the water at all. However, the Italian sentence can be translated into either the simple present tense or the present continuous.
If one translated "Fish live in water" to Italian, it would be the one given. If one translated "The fish live in the water" to Italian it could be the same Italian sentence. The Italian sentence is ambiguous as to general or specific. If one didn't have clues through context and wanted to remove the ambiguity that it is specific, one could use "Quei pesci vivono nell'acqua" (or "Quei pesci vivono quell'acqua"). We have no context, so translating to general or specific are both possible.