Um what isn't sushi raw fish?
The only defining cahracteristic to sushi is how the rice is prepared.
It can be filled with anything: raw fished, cooked fish, other meats, or even just veggies
You can get it cooked (tempura) if you prefer
Tempura is a method of battering and deepfrying, their are other varieties of cooked meats
The first time I had sushi I didn't know it was wasabi I thought it was just avacado or something. I spread the entire ball of it on one piece of salmon and dear god it was hell.
OH GOD WHY
I've found I don't really like nigiri, I prefer rolls which have other flavors to go with it so the fish taste isn't as strong