"One can use salt to dry fish."
Translation:Oni povas uzi salon por sekigi fiŝojn.
Not necessarily. Suŝio estas el rizo kaj fiŝoj is used, as is el rizo kaj fiŝaĵo. One wouldn’t say jerky is made from sekigita bovino but from sekigita bovaĵo—but fish are often (usually, in the case of small fish, I think) dried whole, unlike whole cows.
I think it’s a question of whether the foodstuff is almost entirely separable from the source as a concept (like beef vs. cow) or if they remain pretty close (like fish). In English, we tend to mark this delineation by whether the word is different (beef, pork, venison) or not (chicken, fish), but the semantic delineation is cross-linguistic even when there aren’t different words for the source vs. the food (or, as in Esperanto, universal, systematically different words).
You butcher a cow, not beef, but you dry beef, not a cow. So you see here in English, the indefinite article also marks this—you catch and clean a fish (fiŝon) and dry a fish or dry fish (fiŝon—or, possibly also fiŝaĵon) and eat fish (fiŝaĵon). But you can be clear you ate a whole fish by saying you “ate a fish”, so possibly you could do the same saying Mi manĝis fiŝon? I’m not sure.
…And I thought that read “5 days ago”, not “5 years ago”, or I wouldn’t have responded. But maybe this will be of interest to someone in the future.
p.s. We’re often reminded here and on other learning sites that Vikipedio is not edited by the most fluent Esperantists and so shouldn’t be used for learning the language, but fluent Esperantist Wikipedians do try to edit it as they can—which means that you can usually at least trust article titles if they’ve existed for a while and been edited by multiple people. And I see there’s such an article for Sekigita fiŝoj. So that’s another data point.
Yeah, but we have to be careful trying to force English grammar onto Esperanto words. And by be careful I mean to not do it, because Esperanto has it's own grammar. ;)
I'm still trying to wrap my head around this one, too, but ĵetkubo's reminder of the -aĵo affix is really helpful!