Uh, yikes!
1) How do you know direct sun doesn't bother your dog? Ya ever asked him? We exist and accomplish things in direct sun. That in no way means we are not bothered by it. Canine eyes are very sensitive, actually.
2) Fish are not dogs. And, dogs are not fish.
3) Light being refracted does not necessarily render it unbothersome.
4) Where just predators?
5) Claim that dogs ain't got no dang eyelids (or paws, lungs, or naughty bits) and people are gonna give ya a hard time. Ya just can't spout off something that hurtin' and then whine when you're called out. Stop it. It makes you look like a sissy.
6) There is usually not a need for someone offering rightful, astonished criticism to chill out.

As for the OP, 20 acres is a pretty decent sized little lake - close to 900K sq. ft....15 football fields - and it's unlikely to be as uniform as you fancy. A jon boat, trolling motor, and depth finder would likely offer some enlightenment. A systematic approach to the problem, including careful finesse lure presentations during solunar major periods mid-day, should eventually do something. If a rather robust 4x4 and a shallow draft aluminum boat with a good depth finder is suitable for your situation, I wouldn't mind taking ya out and doing a survey - I like tackling problems.

That said, I've simply seen fish go on great bites one day, then shut off for several days. Heck, come to think of it, it's kindasorta the story of my life.

Dogs don't have eyelids??????? What planet are you from??? Pluto??? So you have a dog that doesn't have eyelids. LOL and you are giving advice on here. You are too funny.
Just wondering, are you actually older than 3 years old??

One thing is for sure, you win the award for posting the goofiest information on this forum,EVER.

My dogs are mutants with eyelids.

My dog absolutely has eyelids. I don’t think you’ve ever met my dog, but if you have, you’d know he has eyelids. If you’ve ever met any digs, you’d know they have eyelids too.

^^^^that dog ain’t got no eyelids!^^^^.

The answer to the original post as to why he can catch a bunch of fish one day, and none the next, more than likely has to do with the barometric pressure for each day. 29.92 or lower ='s good fishing days.

Know what strain of largemouth were stocked? The Florida strain tends to be a little more moody than the northern strain.

Could be several explanations. If food is abundant, they won't be as aggressive towards artificial lures and will probably only feed in prime periods rather than taking advantage of what meals present themselves. As others mentioned, weather and barometric pressure plays a role, especially on Florida strain largemouth. Maybe your persistent fishing is getting them lure-wise, bringing the overall average bites/day down making the weak days seem even weaker.

Is there any cover in the lake? Brush/log piles, rock piles, downed trees and artificial cover give them something to concentrate on rather than just roaming the banks in a coverless system.

Try speeding your presentations way up, or slowing way down. If they're moody, your best bet is to shock them into a reaction bite by burning something by them or talking them into biting with a good looking slow soak.

It's obvious they just like dicking with you. Fish once a week.

what has this forum became? just wow...

I think all fish, fresh and saltwater run on cycles. I swear shark fishing from my favorite spot runs in 2 nights on 3 nights off cycles. I bet if you fish consecutive days often enough you see similar patterns in all fish.