Photo of backswimmer, side view

    Backswimmers

    About 32 North American species in the family Notonectidae
    Photo of a spothanded crayfish viewed from above on white background.

    Crayfishes

    About 36 species in Missouri
    ellipse

    Ellipse and Bleedingtooth

    Venustaconcha ellipsiformis and V. pleasii
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    Photo of a leech

    Leeches

    Various species in the subclass Hirudinea
    Photo of a midge fly larva crawling on a rock in an aquarium

    Midge Fly Larvae

    Nearly 1,100 species in North America
    Orangethroat darter female, side view photo with black background

    Orangethroat Darter

    Etheostoma spectabile
    Photo of a ramshorn snail on a wet rock.

    Ramshorn Snails

    Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
    Illustration of a redfin darter male in breeding colors.

    Redfin Darter

    Etheostoma whipplei
    exclamation mark

    Endangered

    round pigtoe

    Round Pigtoe

    Pleurobema sintoxia
    Image of a southern redbelly dace

    Southern Redbelly Dace

    Phoxinus erythrogaster
    Photo of an aquatic tubificid worm among rocks in an aquarium.

    Tubificid Worms (Tubifex Worms)

    Tubifex spp. and other aquatic tubificid annelids
    Photo of a northern, also called virile, crayfish.

    Virile Crayfish (Northern Crayfish)

    Faxonius virilis (formerly Oronectes virilis)
    Photo of a White River crawfish.

    White River Crawfish

    Procambarus acutus