1. 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))

2. 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))

3. 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))

4. 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))

5. 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))

6. 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))

7. 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))

8. Adipose fin
Axillary process
Eddy and Underhill (1978)

9. 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))

10. 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

11. 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)