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

    Aquatic Spiders

    Dolomedes spp., Tetragnatha spp., and others
    Photo of a belted crayfish, also called Big River crayfish.

    Belted Crayfish (Big River Crayfish)

    Faxonius harrisonii (formerly Orconectes harrisonii)
    Bigmouth buffalo side view photo with black background

    Bigmouth Buffalo

    Ictiobus cyprinellus
    Blackspotted topminnow side view photo with black background

    Blackspotted Topminnow

    Fundulus olivaceus
    Blackstripe topminnow, male in spawning colors, side view photo with black background

    Blackstripe Topminnow

    Fundulus notatus
    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
    Photograph of Ebonyshell freshwater mussel shell exterior view

    Ebonyshell

    Fusconaia ebena
    exclamation mark

    Endangered

    Photo of a freckled crayfish.

    Freckled Crayfish

    Cambarus maculatus
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    giant floater

    Giant Floater

    Pygandon grandis
    Photo of a giant water bug

    Giant Water Bugs

    Species in the genera Abedus, Belostoma, and Lethocerus
    Venomous Icon

    Venomous

    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 golden crayfish viewed through the surface of creek water.

    Golden Crayfish

    Faxonius luteus (formerly Orconectes luteus)
    No photo available

    Goldstripe Darter

    Etheostoma parvipinne
    exclamation mark

    Endangered

    Photo of hellgrammite

    Hellgrammite

    Corydalus cornutus
    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
    Image of a Johnny darter fish

    Johnny Darter

    Etheostoma nigrum
    lilliput

    Lilliput

    Toxolasma parvus
    No photo available

    Longnose Darter

    Percina nasuta
    exclamation mark

    Endangered

    Photo of a longpincered crayfish.

    Longpincered Crayfish

    Faxonius longidigitus (formerly Orconectes longidigitus)
    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.
    Illustration of a northern brook lamprey

    Northern Brook Lamprey

    Ichthyomyzon fossor
    Image of a northern rock bass

    Northern Rock Bass (Goggle-Eye)

    Ambloplites rupestris
    Photo of a ramshorn snail on a wet rock.

    Ramshorn Snails

    Gyraulus, Helisoma, Menetus, Micromenetus, Planorbula spp.
    Photo of a ringed crayfish.

    Ringed Crayfish

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

    Saddleback Crayfish

    Faxonius medius (formerly Orconectes medius)
    Image of a slender madtom

    Slender Madtom

    Noturus exilis
    Spring cavefish side view photo with black background

    Spring Cavefish

    Forbesichthys agassizi
    exclamation mark

    Endangered

    Photo of stonefly naiad on a rock underwater

    Stonefly Larvae

    There are hundreds of species in North America
    threeridge

    Threeridge

    Amblema plicata
    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
    Photo of two water penny beetles clinging to a wet rock.

    Water Penny Beetle Larvae

    Beetles in the family Psephenidae
    Photo of a collared water scavenger beetle showing back.

    Water Scavenger Beetles

    Beetles in the family Hydrophilidae
    Photo of a water scorpion, genus Ranatra, captured in a jar of pond water.

    Water Scorpions

    Ranatra spp. and Nepa apiculata
    Photo of a woodland crayfish.

    Woodland Crayfish

    Faxonius hylas (formerly Orconectes hylas)