fhouse is correct, in English, "fish" refers to both "fish (sing.)" and "fish (pl.)".
In Spanish however, "pescado" refers to "fish (sing.)" whereas "pescados" refers to "fish (pl.)".
Therefore, the women eat (one) fish:
"Las mujeres comen pescado."
In this case however, it is the plural form. The women eat (more than one) fish:
"Las mujeres comen pescados."
@goatmeal Well, your statement is not 100% accurate as far as Spanish is concerned as "pescado" can refer to plural and also to singular.
Pescado refers to a single countable unit of fish, a single fish. Thus, you can say "un pescado, dos pescados..."
But pescado can refer to an uncountable amount of fish. Thus, "las mujeres comen pescado" is ok and doesnt mean that they eat a single fish. Here "pescado" stands for "fishy type of food" and is uncountable. Here "pescado" could be replaced for other uncountable matters like "carne" (meat), etc.