A neritid gastropod is a type of snail that belongs to the family Neritidae. There are many synonyms that are used to refer to this type of snail, such as nerite, neritid snail, and nerita. Other synonyms include river snail, freshwater snail, and rock snail. They are commonly found in both freshwater and saltwater environments and are known for their distinctively-shaped and patterned shell. These snails play an important role in the ecosystem as they help to control populations of algae and other aquatic plants. Despite their small size, these snails are popular among collectors due to their unique patterns and colors.