Shellfish are a diverse group of aquatic animals that have a hard outer shell. They are commonly found in oceans, rivers, and lakes. There are two main types of shellfish: crustaceans, like shrimp and crabs, and mollusks, such as clams and oysters. Shellfish are popular in many cuisines around the world and are often enjoyed for their unique flavors and textures. These creatures play an important role in marine ecosystems, serving as both predators and prey. Many people also harvest shellfish for food, making them a significant part of the fishing industry. However, it's essential to manage shellfish populations sustainably to protect their habitats and ensure they remain available for future generations.