What is actually the shrimp's vein...

For larger shrimp, it’s recommended to remove the vein as it’s more visible and likely to contain debris. In smaller shrimp, it’s often left intact since the impact is minimal. If you’re preparing delicate dishes like ceviche or aiming for a clean presentation, it’s best to remove it.

To remove the vein, make a small cut along the shrimp’s back, lift the vein with a knife tip, and rinse the shrimp under cold water.