Canned TUNA! only. Fresh has too much moisture.
BUT, you can use canned salmon, too. That's awesome. Smoked TUNA!, canned or not. Smoked salmon. I might try it with canned halibut at some point.
It's great with crab, too. But ya gotta press out the moisture.
Haven't tried it with shrimp, but that's probably a really bad idea. I love shrimp.
You can substitute the red bell pepper with other kinds of peppers, too. I made it once with Pasilla peppers. It turned the whole thing green, but it tasted great. Just not real pretty.
I love this recipe! Making it again tonight.
Try it with swiss cheese sometime.
Or smoked gouda.