Yes, taxidermists do mold fish, but usually not crawfish. For crawfish we just injected them with a solution, positioned them on cardboard with T-pins, then let dry and finish with paint, sealer, etc. As for fish, there is tons of info on taxidermy.com on how to mold them. Most likely smaller fish as even with crawdads, a lot of them freeze dry them and use the orginal, but that would not work in this case wanting to mold one to make a bait with.