I have a Rapala electric knife. I found a web page pdf for the knife that said do not put the blades in the dishwasher. What could hurt steel and a bit of plastic? If rinsing and scrubbing them off at the sink after cleaning fish is ok, so be it, but just curious what that recommendation could be about.

I've always chunked em in the dishwasher

Never hurt mine.

Dishwashers are tuff on knives it's the quickest way to dull them

Dishwasher soap can chemically remove the sharp edges on some knives blades, shouldn't be an issue with electric knife blades.

Tom 

I got this weird little trick is called a knife sharpener!

I wouldn't put any knife blade in the dishwasher.  The high heat and caustic detergents can dull a blade very quickly.