The pond where we store our pure florida LMB broodstock has been set up with threadfins and tilapia only. It has been successful so far, keeping the equivalent of 200 bass per acre fat and happy. We keep the water fertilized with cottonseed meal so that we get optimal recruitment of shad and tilapia forage.
Here's what you should watch out for down south: Tilapia are terribly difficult to harvest via electrofishing. I don't know exactly why this is. You'd have to rely on a different method for harvest.
If you keep your water fertilized then threadfin shad can be a good long-term forage base, even in a predator heavy pond. In my opinion, the key to success with shad is not depth or structure, it is about the density and type of plankton bloom. I have experience with successful shad stocking in small ponds. ALL successful pond have the same type of "meaty" bloom, characterised by greenish-brown water with 12"-20" of visibility.
Small ponds that are super-clear, muddy, chalky, or overgrown with submerged vegetation aren't candidates for shad. The best way to achieve this type of bloom in a small pond is to control submerged vegetation and add organic fertilizers over time. One or two applications of 200 lbs cottonseed meal per acre in the spring usually helps, or a long-term feeding program also may encourage a stable "meaty" bloom.
I also might add that all forage fish will perform better in this type of water, not just threadfins.
