Originally Posted by Lighthouse
Now why/how would the transparant head be lighted up on the inside?
Fish and other marine life living at great deepths are usually transparant or red. There is a reason for this. As there is very little light reaching the ocean depths, any pigment is of very little benefit as there is so little light to reflect. However, a good number are red. This is because whatever light does penetrate to those depths is at the other end of the spectrum and will not reflect the red colour thus making the fish invisible.
A number of other predatory cretures generate their own light. This is to attract other forms of life to them which they then pray upon. It is also possible that light emittance is used to attract partners.
I assume, in this case, the "light in the head" to be the camera's own light source which, because the fish is pigmnentless and nearly transparent, is being reflected from the eyes and other organs in the head.
Aye // Stephen