32% is the suggested min. for growout of YP. For small fingerlings what you suggested would be better (40/10).
Yellow Perch, Lake Perch
Perca flavescens Drawing courtesy Maynard Reese, 1991.
Fish Iowa! Iowa Dept. of Natural Resources
Common name: Yellow perch, lake perch
Scientific name: Perca flavescens
Production potential: Moderate, due to slow growth of males
Marketing potential: Potential: High
Size: 3-5 fish per pound
Market: Food
Temperature requirements: Growing: 55-78 F
Spawning: 50 F
Lethal: NA
Feed requirements: Protein: 32-40%
Fat: NA
Spawning requirements: Fish spawn in the spring when water temperatures reach 50 F. Eggs are contained within a gelatinous ribbon. A 0.5 lb female will produce 10,000-20,000 eggs. Eggs hatch in approximately two weeks at 53 F. Spawns may be obtained by stripping eggs from ripe females and mixing with milt from males in a dry container, mixed thoroughly and then water is added to activate the sperm and permit fertilization.
Most common
production systems: Ponds stocked at 200,000-300,000 fry per acre for production of 3-5 inch fingerlings. For food fish estimate 1,500-2,500 lbs. per acre.
http://aquanic.org/publicat/state/il-in/as-495.htm From this chart you can see that the Purina suggested products for YP go from 50%/17 to 41%/12.
http://aquamax.purinamills.com/aquamaxproductlist.pdf
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