Some hundred-year-old advertisements are for foods that apparently haven’t stood the test of time. This ad for Ambassador Luncheon Haddies is for canned haddock. I’ve never seen canned haddock at the store – though maybe it was similar to canned tuna.
A Hundred Years Ago 
I guess any kind of fish could be canned. I would probably pass on that.
Canned Finnan Haddie? A dish that used to be somewhat more popular than it is now, my mother-in-law used to make it. I think it probably would be a bit like canned tuna or salmon. So much easier to transport the fresh/frozen fish now.
I found two recipes for its use, one as creamed fish on toast and one of a casserole, similar to tuna casserole with the addition of bread crumbs. It was recommended for salads and sandwiches, and 3 cans were 25 cents in 1920!
Sounds delicious! But then I like tuna, salmon, mackerel, sardines, herring, and anchovies! I haven’t met a canned fish I haven’t liked!!!
Perhaps it will make a return since meat has become so expensive.