I haven't fished it in a few years. The lower, Dauphin County end, is stocked heavily, and has a good number of fish put in it. Problem is, it's a long stretch that's stocked and if the fish don't spread out, and you're not at a spot where some buckets were tossed, you're in for a slow day. Last time I fished that stretch I caught one stocked Brown.
Stony's a bit of an anomaly in that it generally gets more acidic the further downstream you go. Most streams are the opposite. In its headwaters, on the Lebanon County end, there's a limestone diversion well and the PH is pretty good. There's Brookies up there, up to immediately below the well. May be Browns too, but all I've caught is Brookies. As you go west, the tribs that come down off the mountain are all acidic and dead though...Yellow Spring and Rattling Run being the bigger ones. This water all ends up in Stony.