Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 32 results
Photo of an alderfly larva among rocks and gravel in an aquarium.
Alderfly Larvae
Sialis spp.
Alderfly larvae look a lot like their cousins the fishflies, but instead of having pairs of fleshy tails, they have only a single tail pointing straight back.
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.
Photo of a spotted fishing spider perched on the water's surface amid floating duckweed plants
Aquatic Spiders
Dolomedes spp., Tetragnatha spp., and others
A variety of spiders are adapted for live on and around water. Many of these are called fishing spiders. Several have the ability to run across the water’s surface. Some build webs, others do not.
Two pairs of Asian clam shells, still hinged together, showing exterior and interior
Asian Clam
Corbicula fluminea
The Asian clam is a nonnative, invasive species that lives in a variety of aquatic habitats. It has thick shells with distinctly ridged, concentric rings and a yellowish-brown to dark brown shell covering.
Photo of backswimmer, side view
Backswimmers
About 32 North American species in the family Notonectidae
Sometimes called “water bees” or “water wasps,” backswimmers are predaceous and can deliver a painful bite if mishandled. True to their name, they swim belly-up, and their backs are keeled like a boat, which makes back-swimming easier.
Gray, speckled, translucent gelatinous blob cut in half to show structure
Bryozoans (Moss Animals)
Freshwater species in the phylum Bryozoa
Bryozoans are tiny, filter-feeding invertebrates. They create colonies that can be mossy, branching, or round and jellylike.
Photo of caddisfly larva with case made of detritus
Caddisfly Larvae
Various species in the order Trichoptera
The aquatic larvae of caddisflies are famous for building portable, protective cases out of local materials, including grains of sand, bits of leaves and twigs, and other debris. The adults are mothlike.
Two Chinese mysterysnails, out of water, resting on a white surface, with a ruler nearby for scale
Chinese Mysterysnail
Cipangopaludina chinensis malleata (syn. Bellamya chinensis)
The Chinese mysterysnail is a nonnative invasive species quickly taking over urban waters throughout the state. Never release aquarium species or aquarium water into natural aquatic habitats. Learn about and practice clean boating techniques so that you do not accidentally spread invasive aquatic species.
Clam shrimp on a white fabric surface
Clam Shrimp
Cyclestherida, Laevicaudata, and Spinicaudata (orders or suborders)
Clam shrimp have their carapace shaped like a pair of clam shells and they can close it tightly when disturbed. But they are not clams: they have tiny, jointed shrimplike legs and bristly, feathery antennae.
Photo of crane fly larva
Crane Fly Larvae
There are over 500 species of crane flies in North America.
Crane fly larvae are tan or gray grubs that live in aquatic habitats or in moist places on the ground. The harmless adults resemble huge mosquitoes.
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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.