With a usual maximum size of about three inches, N. procne is a slender, silvery creature, the scales outlined darkly for a network effect. There is a rather thick mid-lateral stripe of variable intensity, blackest on males, sometimes invisible. In the former case, it often has a zigzag look, resembling the stripe on Lucania goodei . In sunlight, a gold or even purple stripe overlays the black one. An occasionally sunlit aquarium is therefore the best.
Swallowtails do well in aquaria, eating any fish food.
They are not nasty to each other or other species, but descriptions of breeding procedure raise the possibility of a feisty period. Allegedly males stake out breeding territories and guard nest areas. The latter two share the variable black stripe, general outline, round or blunted nose, and, slightly, the networked scales. Closer inspection will reveal the prominent half-spine at the front of the dorsal fin on the Pimephales , which also has a rounder, plumper body. Used with permission.