fish
The Italian word for 'fish' is 'pesce'. It's used in the same way as in English, to refer to an aquatic animal. Just like in English, it can also refer to the meat of such an animal, as well as being used metaphorically in certain contexts.
I had fish for dinner.
This is a simple statement about what one ate for dinner. The verb 'ho mangiato' is the past tense of 'mangiare' (to eat), 'il pesce' means 'the fish' and 'per cena' signifies 'for dinner'. This phrase indicates that fish was the main dish of the narrator's dinner.
The fish swims in the sea.
This Italian phrase merely expressses an ongoing action or a general fact. The verb 'nuota' means 'swims', 'nel' is a contraction of 'in' (in) and 'il' (the), and 'mare' means 'sea'. This phrase can be used to describe the scene of a fish swimming in the sea.
Fish is a healthy food.
This is a statement about nutrition. 'è' means 'is', 'un alimento' means 'a food', and 'sano' means 'healthy'. The phrase suggests the speaker's belief or evidence-backed knowledge about the health benefits of consuming fish.