Is that mackerel or sardines? I guess it can’t be any worse than eel pie, which I’ve never had and don’t especially want to try. My family still does this “supposedly” Welsh thing on Christmas Eve of eating shrimp cocktails and Cracked Crab, and we have Finnen Haddie (smoked fish) on Christmas day. I’m not sure that’s really something welsh people do but my family thinks it is.