English: The technique known as clearing and staining is used by functional morphologists to stain certain tissues specific colors (like bone-red and cartilage-blue), while digesting unwanted tissues or making them transparent. This technique is great for easily identifying anatomical structures, such as the cartilage-supported maxillary barbels (whiskers) or the prominent barbs on the bony pectoral fin spines of this blue catfish. As catfish grow bigger and age, their spines and barbs wear down, becoming duller. This is a photograph of a cleared and stained specimen created by Noah Bressman at Wake Forest University.