Perch are bottom dwellers so I never fished on the bottom. Small perch are a nuisance on the locator but once you learn what they look like on a flasher you can ignore them.
If there are tons of the small fish in an area, the larger fish are most likely eating well without having to work very hard at it.
I was fishing a local reservoir and found a deep depression that bottomed out at 37 feet. The bottom 4 feet of the flasher looked like it was crawling with fish. Sunfish, crappies and perch are common on this water, so when I saw some random marks at around 13 feet that came and went on the flasher in a short time span I decided to target that depth. I did very well on larger crappies for that lake. In the pail of water they were kept in, those crappies regurgitated a mess of sunfish in the 3/4″ to 1 1/4″ sized range along with several perch about 1 1/2″.
I’d suggest studying the water over the masses at the bottom without having the bottom lock feature turned on. Way too many people get fixed on what is being shown inside the locked feature and ignore what might be above by several feet. Your Christmas tree comment rings a bell regarding the incident I just described and I think the dinks at the bottom are so challenged for food that when something starts to fall down thru the water they buzz right up to grab it only to find its not what they can eat and they slowly descend to the bottom again. Its during this descent that I think feeding crappies using water at mid-column grab these little guys for a snack. Either that or crappies in a neutral mood and resting in deep water levels just above the masses grab an occasional small fry if the opportunity comes along. But I think its more that small fish venture into the crappies’ feeding area when chasing a potential meal from above and become food themselves.
Try dropping your jig or lure down to where the top of the small fish pack stops and work that water depth. Those little suckers up our of their safety zone become food and they fewer there are the better the chance that crappies will focus on them, or better yet, your bait.