From years of experience owning a fish market and filleting 1000's of pounds of fish I will recomend the following.
I would loose the drop point portion, and here is the logic behind it. You want the point at the leading edge. A lot of filleting fish is feel, you're trying to feel the bone structure of the fish, and slide the knife blindly along the skeletal structure.
With the knife you made you would actually be on the spine of the knife and it would be hard to guess if you are riding right along the spine. ( I hope this makes sense, it's the best explaination I can give)
Also I would get rid of the guard and incorporate it into the handle. There is really no need for that kind of protrusion on a fillet knife. The way you have that designed it is going to impede you when you go so skin your fillet. It is going to make the knife ride off the table and that is no good.
I know people will say slimy fish you need to have a gaurd. I will respecfully diagree and tell you this. From years of cutting fish I have only cut myself once where the gaurd would have stopped my hand from sliding up the blade. I was just finished realigning my edge with a steel and as I brought my knife back to the table to go to work, I stabbed into the edge of the table in my haste. End result was a large gash in my pointer finger.
Please take this as constuctive critisism only. Hope it help you out.
Paul