Smoking fish on a WSM, Bad?

Do it, Don.
I've done Salmon on my drum a few times (not cold smoked) and it turned out GREAT! Had no issues with any "after taste". If the fish is fresh, there sould be no smell at all.

I smoke fish all the time in my UDS. Never a problem with it affecting the taste of the next cook. Do it, smoked fish is great :thumb:

I've done hot smoked salmon on my WSM with no trace of the fishy funk afterwards.

I personally would not cook Salmon on on any of my WSM's that I would be using in competition. The Salmon is a pretty oily fish and I've judged comp meats that were cooked on WSM's the next day after a Salmon side category and the smell and after taste were really prevalent. And we have some Head Judges that bring that up at Cooks meetings too.
If it were my only cooker, I suppose it wouldn't be a big deal seeing I could clean it out after each smoke, or if I did a lot of fish I'd have a dedicated fish smoker. (Little Cheif)
Bobby Flay likely used a demo bullet for the show. Trout isn't as oily as Salmon, he was likely hot smoking and it didn't take all that long to cook.

Give it a try, foil the pan and oil the grate so the skin won't stick, and you be the judge.

i've done it several times without problem.

i think any smell or flavor that happens on your next cooks likely come from drippings that are remnant in the charcoal or near the charcoal.

Well I know when I cook brisket, it definitely leaves an aroma behind, never tried fish though. I don't think Harry Soo recommends if I recall, but I'm sure whatever is left behind is not permanent.

My BIL's kettle smells like alder smoked salmon, but, the smell does not seem to get on any of the other meats. Not sure what the deal is, I assume salmon fat is in there somehow, but, does not get on the meat.

Just wash it out after you smoke fish.

Simple solution.