Fish neck no. Skull fish still connected to the spine. Due to this, the front end of the body of the fish has stable streamlined shape, which is necessary when moving in the water, and the head is firmly connected with the body, which is very important, as when swimming, it is the fish's head cuts through the water.
Skeleton fish (roach)
Thus, no neck in fish is the result of the specific nature of their habitat and lifestyle.