Taxonomy & naming
Girard described the species in 1854; the authority in Catalog of Fishes is (Girard, 1854), in parentheses because the species now sits in a different genus from the original. It belongs to Etheostoma, the largest genus of North American darters, in the perch family Percidae. Imperial Tropicals sells it as the swamp darter "Green Swamp", where "Green Swamp" is a locality label; the listing does not say where that is.
Morphology
Imperial Tropicals describes olive to dark green fish with brown mottling. The epithet fusiforme means spindle-shaped.
Habitat
FishBase gives standing or slow-flowing water over mud, sometimes sand, often in vegetation. Its range covers the Atlantic and Gulf coastal plains from southern Maine to Louisiana (Sabine River) and southeastern Oklahoma (Red River), and the former Mississippi Embayment north to Kentucky and southeastern Missouri. FishBase gives a temperature range of 14 to 26 C.
Feeding
Imperial Tropicals says swamp darters spend most of their time on the bottom or perched on plants and decor. Darters in general eat small aquatic invertebrates (genus-level); the listing text the atlas holds gives no feeding detail.
Mating
Courtship and spawning behaviour are not described in the atlas's sources for this species.
Breeding
FishBase records that eggs are attached to the substrate and left unguarded.
In the aquarium
Imperial Tropicals says swamp darters do best in groups of three or more because they are somewhat social, and sells them in packs of three. They are curious and hop around the bottom of the tank. FishBase's 14–26 C range suits an unheated or lightly heated tank.
Conservation
The IUCN Red List classes Etheostoma fusiforme as Least Concern, assessed on 12 December 2011 according to FishBase.