You can warm up potroleum jelly to thin it down and then mix together, im assuming the fish has been brined or else it will spoil.
Glycerine oil or propolyne glycol are good lure bases and can be bought at drug stores usually,glycol is a bit more thin consistency where the glycerin is thicker both are oderless and can be food grade quality and dont freeze.
Using fresh fish added to what i just described and then add sodium benzoate as a preserver.
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