Threadfin Shad Threadfin shad, small pelagic plankton feeders, are native to the central and southeastern United States. They do best in large lakes and rivers not subject to freezing temperatures. Thanks to stocking efforts their range has been expanded.
Like gizzard shad, threadfin sport an elongated dorsal ray. They are a deep bodied, laterally compressed fish. Its mouth is terminal and the upper jaw does not project out, which is typical of gizzards. Their fins generally have a yellowish tint, especially the tail. Coloration is grey to blue along the back and they sport a dark spot on the shoulder. Threadfins form large schools. They generally are shallow water feeders and work the surface at dawn and dusk. A smallish fish, these shad rarely exceed six or seven inches. Like gizzard shad they are sensitive to temperature changes and oxygen levels. Die offs are frequent in late summer and the fall.
When water temperatures reach the upper sixties, typically in May or June, threadfin spawn. They broadcast their eggs over submerged objects in shallow water. The sticky eggs adhere to the structure. Females may lay upwards of 24,000 eggs. Life expectancy seldom exceeds 2 to 3 years.
The young and adults feed by filtering plankton and organic debris by passing water through their gill rakers.