I would create the body using pipe form (left right symmetry), add the paddle tail, then cut the whole thing out for an open pour mold. I probably won't spend too much time on the body details like scales or ribs. 3D printed molds already have some contouring effect. You will need to pour two-tone plastisol: translucent white or clear for the belly and darker color for the back. Hope this helps.
Are your stls shared? I 3d print and pour tons of different plastics, but do not have your fusion skills. Let me know if you want to trade or have me pour some really cool baits in your molds.
