Meet the Black Dragonfish, a predator of the deep ocean where little to no light reaches. Many fish at this depth have bioluminescence along their bodies, but they're all blue or green because that's all fish can see; blue and green wavelengths move farthest through the water. Now, what's so special about that ugly bleepster up there? Take a look under its eye; notice the orange sack? It generates red light. Recall that most fish only see green and blue light, so they don't notice the red light shining on them. Basically, the Black Dragonfish creates its own nightvision.