Colorado has over 40 species of aquatic mollusks, ranging in size from less than a quarter of an inch (2-3 mm) up to nearly 8 inches (190 mm). These include representatives of 8 gastropod families (snails and limpets with one shell) and 3 bivalve families (clams and mussels with two shells).
Range & Habitat: Aquatic mollusks are found in or very near any type of water body in the state. Some, like the giant floater, can be found buried in the bottom of large reservoirs while others are more at home beneath rocks in stream beds.
Diet: Aquatic mollusks help keep water clean by feeding on floating materials in the water column as well as algae, detritus, and other submersed items on the rocks and substrate. Mollusks are also important food items for fish, birds and even some mammals.
Reproduction: Mollusks have very interesting life cycles that can range from self fertilization or cloning to sexual reproduction. They may bear fully formed live young or release a larval stage (veligers or glochidia) which will metamorph into adults.
More information about all these species can be found in, A Field Guide to the Fresh Water Mollusks of Colorado (2.5MB) .
Colorado Parks and Wildlife is gathering information about mollusk populations throughout the state. Please report any sightings to Pete.Walker@state.co.us or by calling 970-842-6312.