samaralex:

New World Transparent Specimens by Iori Tomita

Tomita first removes the scales and skin of fish that have been preserved in formaldehyde. Next he soaks the creatures in a stain that dyes the cartilage blue. Tomita uses a digestive enzyme called trypsin, along with a host of other chemicals, to break down the proteins and muscles, halting the process just at the moment they become transparent but before they lose their form. The bones are then stained with red dye, and the brilliant beast is preserved in a jar of glycerin.”