If you look at an ordinary sea shrimp, it is easy to see that its color is far from the usual store one. Frozen shrimp are usually bright pink. But the freshly caught ones are pale, translucent. Only the more expensive northern ones have a slight pink color. Here are Chinese manufacturers and have worked out the technology of making shrimp attractive.
All beauty is achieved if the shrimp is held in a vat with dye for a couple of minutes. Then they can still be treated with sodium tripolyphosphate solution. This substance will give the krill meat freshness and will also allow better water retention when frozen. That is, the shrimp will be much heavier, with a pleasant glossy ice crust.
Boiled prawns from supermarkets, beer prawns are mostly made in China.
For cheap snacks, the shrimp is not treated with tripolyphosphate but simply dried in the sun for several days, spreading it right on the ground. Then dry shrimp is better cleaned, packaged, and sent to customers.