Humans can't see the ghost fish clearly because the ghost fish has good stealth ability. Ghost fish, also known as transparent fish, is a small and transparent deep-sea fish. They live in the deep sea, their visibility is very low, and their body color is similar to the surrounding environment. By reducing the reflection and scattering of light, they achieve the effect of self-camouflage, thus achieving good stealth ability. In addition, ghost fish can also adjust the skin transparency, light reflection and scattering, and further enhance its stealth effect. Because of the high transparency of ghost fish body, its internal organs and bones will become more transparent and difficult to detect, which makes it more difficult for human beings to observe and identify the shape and characteristics of ghost fish.