right / left handed usually refers to a knife with a "single" bevel. one side of the knife is (near) flat, the other side is ground to an edge.
because of the single bevel geometry, those will tend to "steer" / "wander" in the direction of the flat side.
frankly, not being an expert fish guy, single bevel may not be a good choice for disassembling or skinning a fish/salmon.
to filet, you need a really sharp knife to follow (essentially) the rib cage. a knife that "steers itself" could be problematic.
for skinning all sorts of fish I use a 10" very sharp slicer - i.e. a thin long blade - mine is a Wuesthof Classic; works great. it's not single bevel - equal angle sharpened.
when chatting up a fish, sharp is everything. there is only sharp.