I used to work at an animal shelter and as a result have dished up the vast majority of commercially available wet cat foods at some point (we’d get lots of stuff donated to us). At least what’s available where I live. Not gonna lie there have been a few fish ones where they’ve honestly smelled just like a decent fish chowder and I’ve thought ‘you know, in an apocalypse…’. Some are just chunks of mackerel or sardines in sauce and I eat sardines in sauce all the time lol. You’d have to eat a lot of them to get enough calories though. Kitten food is probably the most calorically dense but you won’t get a lot of flavor or texture options, mainly mystery meat pâté.