hello chaps!

i've modelled this fish a bit too enthusiastically at around 9000 polys and my problem is this;

i'm trying to use blend shapes in order to turn this fish from a baby fish into the fish in the pic.

from what i've been told i model the big fish first and then create a blend shape from the duplicate. by scaling the vertices i can make it smaller but i want to get rid of the pregnant belly and make it more baby like. now there's far to many vertices to do this by hand so i wondered if there's some kind of deformer or another method that may help?

thanks in advance

vin209