I've noticed the same thing with Seneca Lakers. I wonder what the time frame is-does it take years of a particular diet to change a fish's color, or is it seasonal? Can a an individual fish be white in say the summer months when it is pelagic, while orange in the winter if it happens to move in shallow and feed on crustaceans? Just thinking out load...
Re: Spiny Water Flea - The spiny, long 'tail' of this plankton is actually a defense against predation: predators have a difficult time swallowing the crustacean. It's ability to avoid predation in part helps this species outcompete other, native, plankton species. However, maybe planktivorous fish -most salmonids when they are larval or fry- can/are adapting and have found a way to eat the critters...?