Image source: bgmooaz123 | inaturalist.org
The flagfin shiner (Pteronotropis signipinnis) is a species of ray-finned fish in the family Cyprinidae (minnows), in the order Cypriniformes (carp). This freshwater species is benthopelagic and usually occurs over sand near vegetation, in creeks, small rivers, and flowing pools and runs of headwaters. They are found in the United States in the Apalachicola river in Florida, Pearl River in Mississippi, and parts of Louisiana. They are also found in Alabama, but occur rarely. It is small and colourful, growing to between 40 and 55 mm (1.6 and 2.2 in). The body tapers to a narrow caudal peduncle. Much of the sides are covered by a lateral band dark in colour. The caudal, dorsal and anal fins are yellow or red-orange with black marginal rays. Present on the caudal fin base are two bright sulfur-yellow spots, with the region between the spots being substantially darker. The flagfin shiner exists syntopically with the sailfin shiner, P. hypselopterus, and the two can be difficult to differentiate. It can be distinguished by its red fins, yellow tail spots, and smaller nuptial tubercles.
