Mine where already pellet trained , they grew so large that handfuls of pellets every other day becomes expensive . (break LFS fish food down to a cost per lb or oz... yikes).. plus tank was cleaner once I cut down on pellet consumption.
Aquaculture Fish Farming , gaming fish pellet food is just garbage when used in a closed loop.. IMO
So not much choice to me once your fish breaks the 20" mark.