In general I’m more likely to make fish tacos than fish burgers because less work is needed. The last time I made homemade fish burgers, my mix was like this -
Moderate chop on cheap pacific cod from store, fine chop on red onion, green onion, jalapenos and cilantro. Season with salt, and a touch of my favorite hot sauce. Add egg mixed with a dash of lime as a binder. Form into patties and leave in fridge to chill and firm up (30 minutes or so). Using just a touch of remaining beaten egg for adherence, generously apply a coating of panko bread crumbs to top and bottom.
Cook in well seasoned cast iron pan on medium heat until done. I served on some store-bought telera rolls I keep for general purpose buns, but any decent bread would work. I find that since I prefer the slightly chunky bits of fish compared to @alovem, I prefer a softer bun so it’s less likely to fall apart as I chew through ciabatta, but I can’t deny I love ciabatta as well. 