Threadfin shad are wonderful. People with ponds further north (like myself) who cannot use them as they won't survive our winters, have to get more diverse forage to have a thriving forage base but we all wish we could just use threadfin. Threadfin shad are not to be confused with Gizzard Shad, threadfin stay small (4-7") and can be eaten by just about any predator while Gizzard Shad can grow to well over 20" and can overwhelm a pond.

http://www.overtonfisheries.com/StockerFish/ForageFish/ThreadfinShad/tabid/79/Default.aspx

Here is what Bob Lusk had to say about them in another thread:
http://forums.pondboss.com/ubbthreads.ph...amp;Search=true

threadfins are a great idea. Here's why.
We all know that bluegill are the backbone of the food chain. They always have been and will continue to be the item of choice to raise largemouth bass. Threadfin shad are a great second choice in waters where they can live with the lowest risk of dying each winter. They are so prolific that they actually increase the odds of bluegill survival, thus "creating" a new food chain.
Threadfins move out into open water and bass will follow them for the chase. I have seen some fabulous topwater action in July from bass chasing shad in the middle of a lake. For each day a bass is suspended in the middle of a lake, the shoreline forage fish have another day to live and grow. When a lake has spawning threadfins, the statistical odds of bluegill survival increases. The main significance of that factor is that if a bluegill is eaten at 1" of length, that fish weighs less than one pound per thousand. But, if that same bluegill lives an additional four weeks and can grow to 2.5", it weighs at least 15-20 pounds per thousand. If it can make it to 45 days, it weighs 30-35 pounds per thousand and is a more significant forage fish for the size class of bass that needs it the most...those fish in the 15-18" sizes.


Other good links about shad:


http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=90319&fpart=1

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=25747&fpart=1

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=18993&fpart=1

Another good Bob Lusk quote:

Look at bluegill as the backbone of the food chain. They are the meat...the primary food for bass. While bluegill spawn several times a year, their numbers ebb and flow as spawning peaks and drops. While young bluegill grow into the food chain, they tend to congregate in shallow shoreline environments.
Threadfin shad live in open water, only congregating along the shoreline to spawn. The rest of the time, threadfins live and feed in open water. A plankton bloom is crucial to their success. Threadfins spawn continually, all summer long. Baby threadfins can begin having babies after about 90 days of maturing. Threadfins stay small, not growing larger than 7 inches.
The main reason they are an excellent forage fish to use for managing for giant bass is because they utilize an open niche in the lake/pond, are small enough for bass to catch and eat, reproduce as much or more than bluegill, and help increase survival of bluegill, so these backbone fish can keep up the pace as primary food source.
The down side is that threadfin die when water temperatures drop below 42 degrees.
It's not that threadfin are 'better' than coppernose bluegill, or that coppernose are 'lacking' anything at all. It's simply a matter of taking the primary productivity of a food chain and converting it to more fish for bass to eat. The addition of threadfin shad could reasonably double the volume of forage fish available to bass stocked with bluegill only. That's the reason.