FHM evolved to fill niches that were mostly devoid of predators. Such as low quality highly turbid creeks and shallow oxbow ponds. FHM just didn't evolve to handle heavy predation. LMB and YP are excellent predators and will thin out your FHM rather quickly.

I experimented with a 1/3 acre pond of a family friend who wanted it just for swimming but was tired of getting bitten by water bugs. He originally stock it only with FHM. They got so thick that you could take a swipe with your dip net and catch at least 20 to 30 every time without any effort. They didn't solve the biting bug problem so 20 6" LMB were added. In 3 years you couldn't find a single FHM! The biting bugs were gone and so were the FHM...