That pond would be good for them.
As far as feeding goes, be sure to mix in a good pellet with the other foods mentioned. The better pellets have a good nutrional profile that might be missed if the fish gets stuck on one other food. Something with lots of spiulina would be good for the blue coloration. I like Omega Veggie Rounds as their ingredients are superior to most other manufactured pellets (whole fish plus high levels of spirulina and kelp). NLS is another great pellet.
By the way, market shrimp is a great food for the larger specimens. They are fairly cheap (just buy a big bag of frozen shrimp), the fish like them, and they pack on mass.