Northern sunfish
(Lepomis peltastes)

The northern sunfish (Lepomis peltastes) is a North American species of freshwater fish in the sunfish family (Centrarchidae). Lepomis peltastes was traditionally recognized as a subspecies of longear sunfish (Lepomis megalotis) but is now considered to be a separate species. However, this change remains controversial.

Identification
The northern sunfish (Lepomis peltastes) and the longear sunfish (Lepomis megalotis) contain very few physical variations. Both are generally small, vibrantly scaled fish with bright, elongated opercular flaps which give the fish an appearance of an ear. This ear is a key factor in differentiating the two fish. Lepomis peltastes opercular flaps tend to have an outline of white and red, while Lepomis megalotis outlines are strictly white.

Although each species coloration is nearly identical, the patterns which form from these colors are not. The northern sunfish tends to have more of a lateral stripe and speckled turquoise pattern along its sides, while the longear sunfish tends to have spotting on its sides, still in turquoise. Each fish also has war paint all the way from the mouth to the edge of the gill flap in the same color as the speckles or spots. Both also contain olive sides and bright orange bellies. These few differences between Lepomis peltastes and Lepomis megalotis leave these fish incredibly hard to distinguish from one another. In all other aspects, these fish look near identical.

The northern sunfish is usually regarded as a subspecies of the longear sunfish due to little and/or improper justification as to why this fish should be elevated as a separate species. The assertion, brought about by Carl Leavitt Hubbs over three decades ago, has yet to be clarified with ichthyologists.

Habitat and range
The northern sunfish inhabits the uppermost portions of the United States, such as the Saint Lawrence River and the Great Lakes Region, as well as the Hudson Bay, Mississippi River, and portions of Ontario. This fish is found in generally small, quiet, temperate streams or rivers with sandy banks or rocky bottoms. Northern sunfish prefer to be near vegetation where they can avoid strong currents.