The yellow thing inside the shrimp head is shrimp yellow. Shrimp yellow is the egg of shrimp, commonly known as yellow. When the mother shrimp reaches maturity, the head and neck will contain shrimp yellow, so the shrimp with shrimp yellow must be the mother shrimp. Inside the shrimp head are the internal organs of the shrimp, including stomach, liver, heart, excretory organs, antenna glands, bladder and excretory pores.