This pertains to Orange Spotted Sunfish
http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0633.2001.100105.x/fullAn old professor used to talk about a crappie stock in Crab Orchard Lake of southern Illinois that could split into two feeding guilds. One that grew fast switched to fish while a slower growing morph stayed on zooplankton. Looking at lots of crappie and even LMB suggests to me that the capacity for phenotypic plasticity is relatively widespread.
Somewhere I have seen where Green Sunfish in the absence of Bluegill becomes more planktivorous while in the absence of LMB it becomes more bass like.
The plasticity can involve morphology and / or behavior.
