studfish

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several colorful topminnows of the genus Fundulus of the eastern United States, having orange or red dots on the sides.

from The Century Dictionary.

• noun A kind of killifish, Fundulus (Xenisma) catenatus, 6 or 7 inches long, locally abundant in the Tennessee and Cumberland rivers.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) Any one of several species of small American minnows of the genus Fundulus, as F. catenatus.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of several species of small American minnows of the genus Fundulus, such as Fundulus catenatus.