That is actually a Bill Fleming method. He taught it many years ago before his reputation went to hell and he disappeared from the 3D world. It works great putting together a creature though. I remember one of the first things I ever made in LW was a dinosaur this way from one of his tutorials.
The tail looks great. On the dorsel fin, there is more of a curve. You could get that with a bandsaw cut and some point pushing. The head is a little beefier on top. Samething would fix that.
Pretty good for ~200 polys though