Photo of an aquatic isopod in an aquarium, crawling on a rock.

    Aquatic Pillbugs and Sowbugs (Aquatic Isopods)

    Freshwater members of the crustacean order Isopoda
    Photo of a spothanded crayfish viewed from above on white background.

    Crayfishes

    About 36 species in Missouri
    Photo of amphipod on a rock

    Scuds and Sideswimmers (Amphipods)

    Species in the crustacean order Amphipoda