Iowa has about 50 species of aquatic snails. The term aquatic is a little misleading when discussing snails, however. Snails usually crawl along the substrate of a body of water, which can include the edge. Aquatic snails often crawl a short distance out of the water's surface as well.

The list of Iowa's aquatic snails can be found at:

Stewart, T.W. 2006. The freshwater gastropods of Iowa (1821-1998): taxonomic composition, geographic distributions, and conservation concerns. American Malacological Bulletin. 21:59-75.

Snails fall into two general groups anatomically. The snails that breathe with a lung-like organ are called pulminotes. The snails that breathe with a gill are called Prosobranchs. Gilled snails typically have a tough bit of shell-like material, called an operculum, that covers the hole in the shell. It moves out of the way when the snail emerges and covers the opening when the snail re-enters its shell. Another difference is that the foot and head of the snail are separate in the gilled snails and fused in the pulminote snails.

About 20 of Iowa's aquatic snails are Prosobranchia snails, and 30 are pulminotes.