Fish is practically a vegetable,, however fish that definitely aren't vegetables are usually fresh. Fresh Kabeljou (or Bacalhau), Tuna, Monkfish, Sardines, Caviar, Lobster and Crab clearly aren't vegetables.
Borderline vegetables are Snoek (in whatever form, pickled dried or smoked, fresh Hake and fresh Kingklip, Yellowtail in various forms, sea mushrooms AKA oysters and fresh Anchovies.
Any fish that is processed falls into the vegetable category, this includes Anchovy "paste".
Some vegetables are cool though, like asparagus. Pecks' Anchovy paste on buttered toast is like that.
The rest are veggie spreads, and can be relegated to the likes of pilchards in a can, "fish fingers", canned tuna, and "mechanically harvested" chicken.
Wedwo is kak, and in fact does not even deserve to be mentioned, unless we are discussing the semi-practical uses of fish entrails and carcasses.