"The shark's food is the fish."
Translation:Il cibo dello squalo è il pesce.
"Pesce" can be both countable and uncountable; for instance the fish market is called "mercato del pesce". It's more or less the same in English though; "the fish" can be uncountable, but "the fishes" can be used to describe different kinds of fishes.
I was always taught that fishes is not a word. The plural of fish is fish, and the plural of sheep is sheep.
That's true for sheep, but not for fishes: there aren't many instances in one's life when you'd want to use the word, but it definitely exists: http://www.collinsdictionary.com/dictionary/english/fishes. Another word that many ignore is "chickens", the plural form that should be used when speaking about live fowls.
Where are you from? Chickens is a normal word to me. Sometimes chooks. Never fowls.
Oxford says that fish is plural of fish here: http://oald8.oxfordlearnersdictionaries.com/dictionary/fish_1
If this is so, then I pesci should be excepted. The sentence could mean "the single fish", "the many fish", or "the range of different types of fish (fishes, if you prefer)".
Dello is di+lo (so mostly "of the") , dallo is da+lo (so mostly "from the").
Why is it "the food of the shark" vs "the sharks food" isn't there a way to say the food belongs to the shark but start with shark?
Because Italian words (or pair of words) can never have 3 consonants in a row, except "str" and few other cases. In "dell squalo", "ll sq" would even be 4 of them!
It's simply impossible to be pronounced in proper italian and it represents what they call "a fiscal code", as a joke :)