Photo of a spotted fishing spider perched on the water's surface amid floating duckweed plants

    Aquatic Spiders

    Dolomedes spp., Tetragnatha spp., and others
    Gray, speckled, translucent gelatinous blob cut in half to show structure

    Bryozoans (Moss Animals)

    Freshwater species in the phylum Bryozoa
    Photo of caddisfly larva with case made of detritus

    Caddisfly Larvae

    Various species in the order Trichoptera
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    Photo of several prosobranch pond snails crawling on a rock.

    Gilled Aquatic Snails (Prosobranch Pond Snails)

    Over 20 Missouri species in former subclass Prosobranchia
    Photo of a gray-speckled crayfish.

    Gray-Speckled Crayfish

    Faxonius palmeri (formerly Orconectes palmeri)
    Photo of a horsehair worm in an aquarium

    Horsehair Worms

    About 350 species scientifically described.
    No photo available

    Hydras

    Various species in the genus Hydra
    Photo of a leech

    Leeches

    Various species in the subclass Hirudinea
    Photo of pulmonate snail crawling on rock

    Lunged Aquatic Snails (Pulmonate Pond Snails)

    Over 30 Missouri species in former subclass Pulmonata
    Photograph of several mosquito larvae resting at water surface

    Mosquito Larvae

    There are about 50 species of mosquitoes in our state.
    Photo of a ramshorn snail on a wet rock.

    Ramshorn Snails

    Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
    Photo of a red swamp crawfish or crayfish.

    Red Swamp Crawfish

    Procambarus clarkii
    Photo of a St. Francis River crayfish.

    St. Francis River Crayfish

    Faxonius quadruncus (formerly Orconectes quadruncus)
    Photo of stonefly naiad on a rock underwater

    Stonefly Larvae

    There are hundreds of species in North America
    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.
    Photo of a water boatman

    Water Boatmen

    About 125 species in North America in the family Corixidae
    Water springtails congregate in water above soggy dead leaves

    Water Springtail

    Podura aquatica
    Photo of a whirligig beetle viewed from above

    Whirligig Beetles

    Species in the beetle family Gyrinidae
    Photo of a White River crawfish.

    White River Crawfish

    Procambarus acutus