I agree with you here Duxdog even though I've never done this - lol. In my mind, positioning like molding a dead fish for a replica would be the challenge. Not a very difficult challenge either for folks like you with the talent to position it to look natural. It all depends on the talent of the artist - much like carving a body! However, getting exact fit and replicating a 3D object to that perfection by carving it isn't easy. With commercial taxidermy it isn't quite as critical carving a fish body to perfection. But, for competitions or if you want to compare apples to apples I would think this method would be superior. I know everybody has their opinions on which medium in the Art world is most difficult and imo it's replicating something in 3 dimensions. Oftentimes I see folks pushing the "carve your own body" thing and it is the way to go if you can do it to an acceptable level. But, for some they'd be better off purchasing a body that's close because at least the anatomy is there. Myself, I think my carvings are perfectly fine for commercial taxidermy, but probably the weakest link in my skin mounts. I'm always trying to improve here! But, I do love to carve bodies! I think I actually enjoy it more than painting! You get in a zone, very relaxing!