Recently I've watched a bunch of Youtube videos on canned fish. I learned that canned mussels exist, and have tried them; not bad. Maybe better than clams (fine, bland) and oysters (don't recall, diary say "not very good"). I've seen people talk about canned tuna belly as expensive but good; no one around carries it, though (well, haven't tried Whole Foods yet.)
Tonight I tried Ortiz brand, white tuna in olive oil. Ortiz seems highly thought of in Europe. The first thing I found was that the pull tab broke off right away. Not what I want out of my expensive cans. The second thing I found was that can openers still work even on extremely oval cans, so the food was saved.
As for the fish, eh. Solid white tuna. Skipjack/light tuna still has more interest. (Though really, I haven't bought much tuna in a long time, outside of these recent experiments; salmon and sardines have more flavor and nutrients I'm interested in. More sustainable, too.)