The best bait I have found for minnow traps is cheeze doodles.  I put them in a womans stocking so the fish don't get freebies, then fasten it centered in the trap so it doesn't flow to one end.  The trap never needs to be in the water more than 20 minutes.  Try it, you'll want to send me money!

ya pretty much have to have them tagged or there basically free game... no real way to prove there yours ya know so prolly metal plates are best tags rip off to easy