Fooled by a Sucker

1/2 crawler on a #6 hook presented in a hole or current seam. Tighten line, watch tip, wait.

Crawler chunks or Redworms (I prefer redworms) work far better than any other bait, everywhere I've fished for suckers (MN, WI, and CO).  Small hooks help a lot (I like size 8 most the time).  

Sight fishing can be great, or it can work against you (if you are targetting the wrong individuals).  Watch the fish, do you see them eating?  Watch the gills and mouth and watch for them physically distubing the sand/gravel.  On rocks sometimes they really go to town trying to get under it to the tasty goodies.  If they are mostly just sitting there, they aren't eating.  Try another time, another spot, deeper, shallower, faster or slower current.  Ultimately every water body is a little different.  

From everything you've said in your post I feel like time/place is the most likely error.  Keep everything else simple right now.  I've had days on my local river where the summer fishing for Shortheads was best in the early AM and later PM, Silvers often more active after dark.  You get the idea.   

As an additional question, do you know what the most common suckers in the streams you are fishing?  That might provide some insight

 Hi chemicalpotential, thanks for posting this question - it brings up a lot of interesting points about sucker fishing in general.  

From your bio, it says you are from Tennessee.  Not having much knowledge of fishing that area, I looked at the Tennessee Wildlife Resources Agency Guide To Tennessee Fish .  I'm sure you have seen it, but it was a very well-done resource and I'd encourage others here to check it out.  However, it is seriously lacking in the redhorse information!  Too bad.  You would need to look at sampling data to determine which species live where.  

If you haven't already, check out the Redhose Species Pages at roughfish.com/redhorses.

For us that fish in the Midwest, we have lots of rivers with high populations of various redhorse.  Some generalizations can be made about location and patterns - 

• Fishing during or right around the spawn is probably the best action.  
• Shortheads spawn first, generally followed by golden, then silver, followed by greaters and rivers.  Blacks spawn well into June here in MN, but in colder  tributaries.
• Medium-sized rivers are often easiest to locate redhorse in.
• Greaters can thrive between dammed sections of medium-sized streams, while river redhorse do not.
• Most redhorse follow seasonal movements  up and downstream, and understanding this on a particular river will pay off
• In the Fall, fishing can be very good as redhorse travel toward wintering areas.
• In general, a 3-5' run with moderate to fast current and a gravel or rocky bottom is prime redhorse water.
• Stationary fishing with bottom-rigged worms is overall the most effective tactic.  Get your bait to stay in the current and set your rod in a holder to detect light tapping bites which are expected from these finicky fish.
• When prospecting for redhorse bites, use as many rods as legal in those waters.  Place baits way out in the main channel on heavier gear, one on a current break or eddy close to shore, and one in-between, for example.  
• Sight-fishing takes stealth and a keen eye, but can be effective.  Blind-fishing general "redhorse" water with multiple baits is more effective more of the time.
• Circle hooks work very well on redhorse.  Consider using them to increase hookups and prevent deep-hooking.
• A long, light soft rod is preferable for redhorse fishing unless fishing with big heavy weights in larger rivers. 
• Around bridges where flow increases are usually good spots to try
• Dams concentrate redhorse in th Spring.
• Mussels or clams can make good redhorse bait.

I hope some of this might help you.  if you are seeing redhorse in any kinds of numbers they will most likely be catchable, maybe by trying different times of the day.  

Message me.  I'm not the expert some are on here, but I can get with you sometime and show you some stuff.  I'm literally just across the state line from you.