Hi Randy,
I am fairly new to smoking and I haven't smoked fish as of yet, however I do have a cousin who only smokes salmon in his electric smoker. I had recently asked if he uses his smoker for pork or beef and his response was no because he was afraid that the strong odor of the salmon in the smoker may penetrate the meat.
Now I don't know if this is true or not as he hasn't tried it, but he did mentioned that he would be more comfortable giving the unit a good cleaning before he attemped to do so, but then again, that is just his opinion and he really only purchased the smoker for salmon.
Just my two cents worth, I personally really want to try smoking salmon because I hear it comes out great in a smoker, but I am also hesitant because I purchased my smoker primarily to smoke pork or beef. That being said, I checked some other threads in another forum and noticed that there are individuals who do smoke both meat and fish without hesitation and some even smoke them at the same time.
It really is trial and error and I can't see why you can't do both. My opinion is not based on experience, however I haven't seen any posts that would answer your question directly, I also didn't see any that raised any concerns either.
Hope this helps.