Just had a tunafish sandwich for lunch. It's a certainty that most of you would call it a "tuna salad" sandwich. It may be a Southern thing, or it may have been a just-in-my-house thing, but we always called the ingredient in the can "tuna," and the finished product "tunafish."
Other sandwich fixings made exactly the same way did have "salad" in the name: egg salad, chicken salad, ham salad. But it always was, and always will be in my vocabulary, "tunafish."
And the only way to eat a tunafish sandwich is with potato chips. BETWEEN the bread.
Oh, and, extant.