Darters! You definitely have rainbow and banded darters on your area. Possibly orange throat and a few other colorful species. Here's a couple darters I caught this year
I don't think that there is any permits on catch and keep wild fish but only catch and release permit is applicable for fishing.
It's called a fishing license...whether you take the fish home and eat it or put it in an aquarium is entirely up to you and legal as long as you follow all size and creel limits and not take threatened or endangered species. I actually work closely with Pennsylvania fish and boat commission and report species of interest and in return I get to find out places that uncommon species have been collected when PAFBC does the electroshock survey
No, you need to use a net. It's challenging! First you have to find them. They are usually in wide, gravel bottom creeks at about knee deep. Usually in or near riffle sections of clear, clean creeks and rivers.
I use 2 nets with handles. Hold one still and try to coax them in with the other. It takes getting the hang of. They stay glued to the bottom, so you need the one net tight to the creek bed. Kinda steer them in front with the other net. It will take some time to get efficient at it. I used to spend hours to catch one or two, now I can catch 40 or 50 in a day! I usually only keep a couple though.