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 Big Creek crayfish.

    Big Creek Crayfish

    Faxonius peruncus (formerly Orconectes peruncus)
    Photo of a coldwater crayfish.

    Coldwater Crayfish

    Faxonius eupunctus (formerly Orconectes eupunctus)
    Photo of a spothanded crayfish viewed from above on white background.

    Crayfishes

    About 36 species in Missouri
    Photo of a Neosho midget crayfish.

    Neosho Midget Crayfish

    Faxonius macrus (formerly Orconectes macrus)
    Photo of an Ozark crayfish.

    Ozark Crayfish

    Faxonius ozarkae (formerly Orconectes ozarkae)
    Photo of a saddleback crayfish.

    Saddleback Crayfish

    Faxonius medius (formerly Orconectes medius)
    Photo of amphipod on a rock

    Scuds and Sideswimmers (Amphipods)

    Species in the crustacean order Amphipoda
    Photo of a St. Francis River crayfish.

    St. Francis River Crayfish

    Faxonius quadruncus (formerly Orconectes quadruncus)
    Photo of Williams' crayfish.

    Williams’ Crayfish

    Faxonius williamsi (formerly Orconectes williamsi)
    Photo of a woodland crayfish.

    Woodland Crayfish

    Faxonius hylas (formerly Orconectes hylas)