Welcome to the Forum. Glad you got intrigued by your baitfish. ashtonmj is right. You need to address the crowding situation immediately or that tank will crash in any number of ways: Mostly likely, the fish will quickly become stressed do to excess ammonia and warm temps. The minnows will die first. The sunfish will gradually decline and become ill if they can survive the high ammonia. I don't mean to be bossy, but the situation is critical. You need to take at least 60% of those fish out of that tank immediately. Put them in bags in your freezer to use as bait or plant them in your yard as compost. No, I'm not kidding. They are going to die, guaranteed, if you leave them all in that tank. If you have to witness that carnage, you will likely be soured on fish keeping. Better to get it done, like ripping off a bandaid, then drawing out the agony. I'm not kidding... oh yeah, I already said that
I would recommend doing large water changes (with water conditioner) on an every-other-day basis for while. Hard to say unless you get a water test kit to monitor ammonia and nitrite. Usually you can tell, by closely and regularly observing the fish, whether they are stressed and need a water change. Don't feed or feed minimally until you can get the water quality under control. Sounds cruel, but large fish can take that just fine. In the meantime, read this article:
http://jonahsaquariu.../aquabasics.htmLooks like you at least have bluegill, green sunfish and one or more longear sunfish. Can't really tell the shiners. Maybe spotfin shiners or common or striped shiners. If you tell us exactly where you caught them (town, county, river, state), we can make better guesses.
Hope it all works out for you. If they die, just clean out the tank and start with a few fish for a month or so until things stabilize. Really, it's the only way to do it with any consistent success.