If it’s the size of a brook trout or small rainbow, you could definitely cook it whole. Over 18″ or so I treat it just like salmon. Lots of possibilities.
a recipe i use alot and love on lakers is soaking it in apple juice over night, or in your case, until you plan on cooking it tonight. Leave the skin on and throw it on the grill. It’s done once the white fat surfaces on top of the meat. Definitely dont overcook it.