Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 12 results
Photo of amphipod on a rock
Scuds and Sideswimmers (Amphipods)
Species in the crustacean order Amphipoda
Often overlooked by people, but eagerly sought by fish, Missouri’s amphipods resemble shrimplike sowbugs. Scuds live in various aquatic habitats, and several species inhabit caves.
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
Everyone knows about terrestrial sowbugs and pillbugs, but many isopod species are aquatic. Missouri has several isopods that live in streams, ponds, rivers, and caves.
pond mussel
Freshwater Mussels
Bivalve molluscs in order Unionoida
Secretive and seldom seen, freshwater mussels are extraordinarily diverse in Missouri. We have nearly 70 species within our borders. Many are declining, and several are endangered.
Zebra Mussel
Zebra Mussel
Dreissena polymorpha
Zebra mussels are named for their shells, which have alternating light and dark bands. They are a highly invasive nonnative species. Learn how to prevent their spread.
Photo of several prosobranch pond snails crawling on a rock.
Gilled Aquatic Snails (Prosobranch Pond Snails)
Over 20 Missouri species in former subclass Prosobranchia
Gilled snails are one of two main groups of aquatic snails in Missouri (the other group is the "lunged" snails). Gilled snails, or prosobranchs, breathe with gills and possess a hard trapdoor-like operculum. They are most common in the Ozarks.
Hydras
Various species in the genus Hydra
We’ve all seen aquariums and pictures of tropical saltwater invertebrates such as corals, jellyfish and anemones—but did you know that there are similar creatures living in the freshwater habitats of Missouri?
Photo of a freshwater jellyfish
Freshwater Jellyfish
Craspedacusta sowerbii (syn. C. sowerbyi)
You may have heard about stinging jellyfish in the ocean, but did you know that there are similar creatures living in the freshwater of Missouri? Fortunately, they’re harmless!
Photograph of several mosquito larvae resting at water surface
Mosquito Larvae
There are about 50 species of mosquitoes in our state.
The larvae of mosquitoes, often called “wrigglers,” have a large head and thorax and a narrow, wormlike abdomen; they typically hang just below the water surface. When disturbed, they wriggle downward.
Photo of a single water strider
Water Striders
Aquarius remigis; also species in the genus Gerris
Water striders are eye-catching. Water-repellant hairs on the hind and middle legs allow these nimble insects to skate on the surface of the water.
Photo of a pink planarian on a rock.
Turbellarians (Planarians; Free-Living Flatworms)
Dugesia, Planaria, and other genera
Unlike their parasitic cousins in the flatworm group, turbellarians, or planarians, are tiny carnivores or detritus-eaters that glide smoothly across submerged leaves and other objects.
See Also

About Aquatic Invertebrates in Missouri

Missouri's streams, lakes, and other aquatic habitats hold thousands of kinds of invertebrates — worms, freshwater mussels, snails, crayfish, insects, and other animals without backbones. These creatures are vital links in the aquatic food chain, and their presence and numbers tell us a lot about water quality.