Thank you TrevoriuS !! Is the bulk better now or should I make the bulk smaller ?

Your lighting has been improved on the overall, but I actually mend the head itself, I misunderstood the shrimps anatomy haha. So what I mend was the part with the more red mark on it, which contains the brains and whatnot.
Furtherm you should remove the hars black lines on the 'inside' of the body, as well as remove the shade below him - it is distracting and not made to be finished yet, and therefore out of place.
About your further changes: It looks like the lightbulb in the image only affects the head and the first 'bulk', but the rest of the body seems to be affected by a lightsource coming from the other side.