It's an unlikely original sentence, but in English "fish" is used both as a collective noun and as a singular descriptor. I should have thought ψαρια was a reasonable translation here?
You are right! Ψάρια makes more sense in this sentence
It is perfectly fine in the singular as well. I take it to refer more to the type of food rather than the quantity, like "The men eat meat".
You are totally right!
However plural ψαρία is marked wrong.
the discussions's translation says άντρες so i reported it.
σύζυγοι means a couple (when singular it means one of the couple).