Shad, also known as river herring, is a small, bony fish. As an adult, it is valued as a food fish. The young, or fry, however, serve as a baitfish for many freshwater anglers, who use them to attract larger game fish. Shad are notoriously difficult to keep alive in captivity, so a bait well must be specially made to maintain them. It can be worth the extra effort, since shad fry are the preferred prey of many prized game fish species.
Constructing the Well
Shad tanks should be circular for one important reason: Shad require plenty of oxygen to stay alive, and it needs to flow past their gills. In a tank with corners, they will huddle in a bunch in a corner, not enough oxygen will flow past their gills, and they will suffocate. A circular tank keeps them swimming around, and that keeps them alive. Make a basic tank by cutting a 55-gallon drum in half. Fill it with about 1 gallon of water per shad.
Keeping the Shad Alive
Even with the right tank shape, you'll still need an aeration system and a few other tweaks to keep the shad alive in your bait well. Shad become stressed easily, and your most important task in nurturing them is to maintain oxygen levels. Part of this is buying a portable, battery-operated aerator to hang in the bait well. The other part of the equation is to keep water temperatures below 65 degrees, because cool water carries more oxygen. On hot days, this is best done using ice, but don't add it all at once. Lower the water temperature by 3 degrees and don't add any more ice for a little while. You'll need a thermometer to monitor this.
Another way to reduce the stress on the shad is to add 1 cup of of rock salt or sea salt for every 25 to 35 gallons of water, providing valuable electrolytes to the fish. Shad need a certain level of salinity in the water, but do NOT add iodized salt, as it will kill them.
The most complicated part of caring for shad is the chemical composition of the water. The water needs to be nonchlorinated. Even if you're using well water or lake water, when you put in pre-made ice, it might have chlorine in it. You'll need to add a little bit of a chlorine-removing chemical to the water before you put in the shad.
Another chemical concern in keeping shad alive is the ammonia in their waste. If they're in there for anything but a short amount of time, they will defecate, and the ammonia can get too concentrated in the well, damaging or killing them. Your two options are to change the water or add a chemical that absorbs ammonia in fish tanks. It's available at pet shops. Ammonia buildup also can cause the surface of the water to foam, and foam prevents oxygen from crossing through. To prevent foaming, add a little bit of nondairy creamer to the water, which will keep the surface smooth and keep the oxygen flowing.
These chemical problems are best fixed by changing out at least half the water in the tank for fresh water. Chemical fixes are mostly just stop-gap measures, and the best cure for most shad ills is fresh, well-aerated water (although you need to remember to keep putting in the proper ratio of salt).