Photo of backswimmer, side view

    Backswimmers

    About 32 North American species in the family Notonectidae
    Gray, speckled, translucent gelatinous blob cut in half to show structure

    Bryozoans (Moss Animals)

    Freshwater species in the phylum Bryozoa
    Photo of a papershell crayfish, also called calico crayfish.

    Calico Crayfish (Papershell Crayfish)

    Faxonius immunis (formerly Orconectes immunis)
    Common shiner side view photo with black background

    Common Shiner

    Luxilus cornutus
    Orangethroat darter male in spawning colors, side view photo with black background

    Darters

    Etheostoma, Percina, Ammocrypta, and Crystallaria spp.
    deertoe

    Deertoe

    Truncilla truncata
    elktoe

    Elktoe

    Alasmidonta marginata
    ellipse

    Ellipse and Bleedingtooth

    Venustaconcha ellipsiformis and V. pleasii
    fragile papershell

    Fragile Papershell

    Leptodea fragilis
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    giant floater

    Giant Floater

    Pygandon grandis
    No photo available

    Hydras

    Various species in the genus Hydra
    lilliput

    Lilliput

    Toxolasma parvus
    Southern redbelly dace male in spawning colors, side view photo with black background

    Minnows

    Notropis, Cyprinella, Hybognathus, Luxilus, and others
    mucket

    Mucket

    Actinonaias ligamentina
    pink heelsplitter

    Pink Heelsplitter

    Potamilus alatus
    plain pocketbook

    Plain Pocketbook

    Lampsilis cardium
    Photo of a ramshorn snail on a wet rock.

    Ramshorn Snails

    Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
    Red shiner side view photo with black background

    Red Shiner

    Cyprinella lutrensis
    round pigtoe

    Round Pigtoe

    Pleurobema sintoxia
    spike

    Spike (Ladyfinger)

    Elliptio dilatata
    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 pink planarian on a rock.

    Turbellarians (Planarians; Free-Living Flatworms)

    Species in genera Dugesia, Planaria, etc.
    wabash pigtoe

    Wabash Pigtoe

    Fusconaia flava
    Water springtails congregate in water above soggy dead leaves

    Water Springtail

    Podura aquatica