Anguillidae (eels) Eel-like body (long, slender) Terminal mouth; jaws Small opercle Small scales; smooth skin Long dorsal fin continuous with caudal, anal fins; no pelvic fin Homocercal caudal fin Pennsylvania Fish and Boat Commission American eel (Anguilla rostrata))

Anguillidae Catadromous Nocturnal movements (can move over land) Females migrate long distances (15 years in fresh water); males remain near coast Nocturnal movements (can move over land) 3 larval forms (leptocephala, glass eels, elvers) Uncommon in Iowa; large rivers American eel (Anguilla rostrata))

Clupeidae (herrings, shads) Laterally compressed Silvery scales Saw-tooth margin (pointed scales) on abdomen (belly) No lateral line Fins lack spines Caudal fin homocercal, forked Pennsylvania Fish and Boat Commission gizzard shad (Dorosoma cepedianum))

Clupeidae Diets primarily zoo-, phytoplankton; gizzard shad strain organisms form soft sediments Gizzard shad an important food web component in lakes and reservoirs with soft bottoms Ohio Department of Natural Resources gizzard shad (Dorosoma cepedianum))

Hiodontidae (mooneyes) Laterally compressed Silvery color Large eye Part of belly sharp/knifelike, but no saw-tooth margin Lateral line present Fins lack spines Caudal fin homocercal, forked GLERL/NOAA mooneye (Hiodon tergisus))

Hiodontidae Diet consists of small animals, including fishes Sportfishes where they are common (e.g., western Canada) Uncommon in Iowa; present in large border rivers University of Alberta Department of Biology goldeye (Hiodon alosoides))

Salmonidae (trouts) Terminal mouth Small scales Fins lack spines Adipose fin Axillary process at base of pelvic fin Caudal fin homocercal, squared or forked brook trout (Salvelinus fontinalis))

Adipose fin Axillary process Eddy and Underhill (1978)

Salmonidae Cool/cold waters Prey on invertebrates, fishes Economically important sport/food fishes Brook trout native to northeast IA; 2 nonindigenous species propagated, stocked (some natural reproduction) Salmonidae Virginia Tech virtual aquarium brook trout (Salvelinus fontinalis))

Umbridae (mudminnows) Terminal mouth Lateral line absent Fins with soft rays Dorsal, anal fins toward posterior end of body Caudal fin homocercal, rounded New York State Department of Environmental Conservation central mudminnow (Umbra limi)) University of Michigan Museum of Zoology

Umbridae Inhabit swamps, ponds Very tolerant of low oxygen concentrations, drought Bury themselves in mud Prey on invertebrates University of Michigan Museum of Zoology central mudminnow (Umbra limi)