I have never tried to dry fish in the dehydrator, but I know some people who salt cure fish. They just use a big wooden barrel and put salt on the bottom. Then they layer fish and salt up to the top and leave it to cure. You have to soak it over night before you can use it to get rid of the salty taste, but it is pretty good. This is the same way the Indians and the pioneers used to do it.
I have never actually tried to salt cure it myself, but I am familiar with the process and I have eaten some. In my personal opinion that kind of fish works better with some kind of sauce instead of just plain salt cured fish.
I would be scared to salt cure anything because I would probably do it wrong. I also don't think I could live with the smell of curing fish for too long. I would try the dehydrator. The settings are usually marked and you could marinate it first if you like.
My grandfather used to salt down herring when I was growing up. We wouldn't eat it because it was just so salty. I prefer freezing any fish I want to save. With fish markets just around the corner, we usually don't even bother with the freezer. Fish just have that smell that permeates everything.