Field Guide

These diminutive mollusks are the smallest of Missouri’s freshwater mussels.

This endangered native mussel lives in flowing waters of large streams among gravel and cobble.

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.

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.

Of Missouri’s two species of freshwater shrimp, the Mississippi grass shrimp is by far the most common and widespread.

Bryozoans are tiny, filter-feeding invertebrates. They create colonies that can be mossy, branching, or round and jellylike.

Like many aquatic insects, these large oval beetles prey voraciously on other aquatic organisms. Excellent swimmers, they fly well, too, and are often attracted to lights.