Hi Evie,
I tried to send this earlier but it disappeared.
Yellow perch don't grow as fast as tilapia, but if they are sorted and sized regularly some would be ready in about 6 mos. The females will get about 1/3 larger than the males.
My greenhouse is 2/3 shaded with a silver tarp, it helps with algae and heat.
Check with your fish and game dept. and Aquaculture Unit of University of Georgia college of Agricultural and Environmental Sciences about growers in your area.
Meal worms and earthworms will work if gradually introduced with their feed.

Ironfish