I would start with YP. If you can arrange a feeder setup I would get the pellet trained YP. You will get the best growth of your perch and the most perch in 1/4ac if you feed pellets. You can get a high quality dependable economical feeder if you just buy just the dispenser mechanism kit and attach it to a 5 gal bucket. Or buy the hanging feeder; both are now on sale. You will need a dock to hang the feeder from for most all around benefits from a hanging feeder.
http://www.texashunterproducts.com/texas-hunter-12-volt-wildlife-feeder-kit/#.Wnn4P0xFxZUOr the hanging feeder.
http://www.texashunterproducts.com/hanging-fish-feeder-with-hanging-bracket/#.Wnn4r0xFxZUYou can grow YP in a pond without feeding but the sizes and numbers will be noticibly less than if they were pellet fed. Same is true for BG. If you use YP without pellets then get your fathead minnows established in spring and stock YP in fall. usually 6-8 SMB in 1/4ac are enough to easily control YP offspring. Adult YP also eat some small 1"-3" YP.
My 1st choice for predators of YP would be HSB and smallmouth 2nd best. HSB won't reproduce and SMB have often have limited reproduction. Too many predators crop too many of the YP and the panfishing numbers suffer a lot. If you don;t like the YP fishery you can always add BG&LMB and then in a few years that combination takes charge of the community.
Are the leeches small ones or large dark colored ones? Free living small fish leeches are common in ponds and YP and some fish may help a somewhat to control them. The small fish leeches are not blood sucking forms. They live on fins of fish and in the organic sediments eating primarily organic materials. Leeches usually arrive in ponds via turtles.
