The red solid on the head of the Roche shrimp is usually the shrimp's reproductive gland, which is more common in female Roche shrimp.
In most cases, this part is edible as it is rich in protein and fat, has a strong umami flavor, and is considered a delicious dish by some people.
However, if the shrimp's head shows abnormal color, has an odor, or the shrimp body has died or spoiled, the entire head, including the red solid, should not be consumed to avoid potential health risks such as food poisoning.