Backyard Aquaponics
A place to discuss aquaponics

I've been reading up on some research on tilapia aquaculture. Most say that they should receive natural sunlight for 10-12 hours per day, yet I've noticed most people shade and/or cover their FT's. Is this to keep the water cooler for their plants, control algae growth, or something else. I'm adding a spa for new FT, and want to keep the fish happy...not as concerned about the plant side for this project.

Its is for algae control and partly heat control as you said.
I dont believe in these things, i tend to think the more natural environment the better for the fish.
Every animal needs sunlight, Most fish when kept in aquariums (no sun light, bright coloured objects in the tank) tend to be dull, place them into a muddy bottomed natural pond in the sun and thier colours increase - this is a huge issue with "rainbows" in the aquarium trade - most that you see in the stores are almost clear/white, yet should be a darkish grey with bright colours at certain angles.

If your main objective is the fish are happy, give them sunlight, make sure there is always a shaded area so they can escape it too.

There are studies that suggest that many fish do better with "light" but whether that is full sunlight or shade is often not documented in the studies. Generally the studies look at how well the fish do with how many hours light. From memory one study found that Iranian Rainbow trout did better with 18hrs of light per day whereas French trout did better with 24hrs of light per day.

I give my tilapia full sunlight in my small 50 gallon "pond" -- I do not see as a lil bit of algae a problem. The fish actually eat it and as long as your plants are big enough to out compete, they will not be hurt.

If you start seeing a bloom of algae -- cut back on sunlight and feeding for a few days until balanced.

I used to be obsessed with preventing algae growth when I was using a glass fish tank until I realized I was overcleaning it for aesthetic reasons. Using a black foodgrade plastic tub as the fish pond helped temper by OCD.