I'm not sure they specifically swim around looking for a specific type fish, they are opportunistic aggressive feeders that eat the first thing that will fit into their mouth. The do patrol the BG beds and shorelines where easy meals are found, so the know where to find food. The odds are in your favor with a nice forage base that the LMB are eating CNBG. It's rare for me to find a LMB in the stomach contents of one I clean, it's almost always BG & bugs.
