Threadfin shad (Dorosoma petenense) have been referred to as “bass candy” because of the largemouth’s strong preference for them as a prey fish. Shad are filter feeders, roaming open water to feed on plankton. For this reason they seldom do well in unfertilized ponds. They are very high in protein and are a soft-rayed fish, meaning they do not have the hard spines in their dorsal fin that a bluegill does; this trait combined with their fusiform shape (bluegill are compressiform, i.e. more rounded) makes them easier for a bass to swallow in larger sizes. They seldom exceed five inches in length, so they stay in the size range ideal for bass to eat. Largemouth will typically engulf several shad at once when feeding on them, attacking the middle of a school, oftentimes at the surface. The one drawback to threadfins is that they are subject to winterkill when the water temperature drops below 45 degrees, so they typically have to be restocked every two to four years.