Image source: Daniel Folds | inaturalist.org
Scarlet shiners get their name from the bright coloration of breeding males, who display a vibrant red on their dorsal, caudal, pelvic, anal, and pectoral fins. The dorsal fin often has a dark blotch at the front of its base. Females and non-breeding males tend to display less distinct coloration on their bodies besides faint red on their fins. Average length is 2 to 3 inches (5 to 7.5 cm), with a maximum of 4 inches (10 cm). Scarlet shiners can be distinguished from the redfin shiner (L. umbratilis) by the four to eleven saddle bands or tiger stripes over the back and upper sides, which can be seen more clearly on males, and have more slender bodies that are laterally compressed. They also have fewer anal fin rays, averaging nine to eleven. Non-breeding males and females still have the silver-blue coloration and the typical cryptic coloration of dark on top and lighter white or cream colored belly. Breeding males of both species develop tubercles on their heads; however, L. fasciolaris generally does not have tubercles on its cheeks, and the lower jaw bears one row of tubercles versus two in L. umbratilis. Scarlet shiners live in subtropical, benthopelagic freshwater environments. Scarlet shiners thrive in waterways that have clear water, and they tend to occupy the higher gradient streams with coarser substrates. Typically, the habitat is situated around the Ohio River basin, but they range down as far as Eagle Creek in Kentucky. The species can be found specifically in the southwestern part of Ohio down to the Scioto River and westward, reaching the Little River basin in Tennessee then connecting to the Tennessee River to flow down into the northernmost parts of Alabama and some areas within West Virginia and Virginia. Scarlet shiners have also been thought to be introduced in certain waterways in Ohio, such as the Ohio River basin to the Muskingum River drainage. Other areas where one may encounter scarlet shiners are in the Cumberland drainages in Kentucky and Tennessee along with the ones in Alabama, Mississippi, and Georgia.
