[Sc-aquaponics] Food Sources & Duckweed

[Jeff Bracken]

What kind/brand of food source would you recommend for comet goldfish 
and shubunkins in a 275-gallon IBC aquaponics system?  Most of our 18 
fish are between 4-6" in length.

Has anyone grown duckweed as their primary (or exclusive?) food 
source for their fish in an aquaponics system?

I've read online about the use of duckweed, but I'm really wanting to 
learn more from those who might have done this.

Thanks for any insight you can offer.

Jeff Bracken
bracken5 at columbus.rr.com
Chemistry Teacher
Westerville North HS
Westerville, Ohio