Silver-colored fish, such as herring, sardines and sprat, are bending the laws of physics, according to a new study published in Nature Photonics. The ability allows the fish to become invisible to predators. As researchers Tom Jordan and Julian Partridge from Bristol University explain, reflective surfaces polarize light, a phenomenon that fishermen or photographers overcome by using polarizing sunglasses or polarizing filters to cut our reflective glare. The scientists found, however, that silvery fish have overcome this basic rule of reflection.

The fish’s skin contains multilayer arrangements of reflective guanine crystals. It was previously thought that fish skin would fully polarize light when reflected. As the light becomes polarized, there should then be a drop in reflectivity. But that’s not what always happens, as it turns out.