I like to take 2 lbs of unsalted butter and turn it into Ghee for sea foods and steaks. Ghee is simply clarified butter and I get a quart out of 2 lbs. I use a Ball wide mouth jar to store it and it keeps up to a year. It is easy to do and takes about 30 minutes or so on the stove on medium to low heat.
I have used rubs but have never smoked fish as good fresh fish is hard to find in my area. I do smoke during the spring and summer months as well as grille. Picture below of my current smoker which really works good. Uses Propane for heat source, wood box above the burner, liquid bowl above that in its own slot (show on a rack in picture but not. I have 4 adjustable racks over 8 rails for the food. Easy to set the heat and puts out a lot of smoke with chips lasting about 2 to 3 hours.