So much for wild trout being too “sophisticated” to be bread eaters like hatchery trout. You’re probably “killing” the ST fanatics here with that pic. Anyway, I learned about wild BT eating bread with reckless abandon when I lived in an apartment next to a narrow wild BT stream and saw a female neighbor, who knew nothing about fishing or trout, standing immediately next to a small pool on the creek one day feeding the trout with bread. No fear on the parts of the wild BT as apparently they had become habituated like stocked trout in a hatchery raceway.
If you live close to the Susquehanna or Schuylkill, many tribs have good spotfin shiner populations fall through mid-spring, as there is movement from the rivers into the tribs by good numbers of shiners.In my experience you can find a lot in pools within a the few hundred yards of the mouth or in the case of the Susquehanna power dams, up the creeks within the slackwater and a little farther up the naturally flowing parts of the creeks. Warm may be better in these cases too, but I know of a stream where this occurs that is a good wild BT stream too. When the water is very cold, as in winter, even these fish seek cover, such as under a large boulder that extends out from a stream bank and provides overhead cover in quiet water. Also, I am not suggesting that these streams do not have populations year around, but the numbers are probably lower once the migrants leave for the season.
As for fathead populations in streams, they are largely a rarity in Pa. There are a few, narrow, jump across or nearly so, limestoners on Lancaster Co farms that have great populations of some of the largest fatheads that you will find, but a strong limiting factor on where fathead populations are found anywhere is their inhibited reproductive behavior in the presence of what we would consider to be standard predatory fish. The Lancaster Co streams of which I speak are predator free.