silversides work great for me! for one that small, i would use the head and guts only and remove the flesh from behind the torso!
i have a 4 year old PBTA, i feed it two 3"-4" silverside every week. it was about 4" in diameter when purchased, today its about 16" in dia.
and no, its not for sell. i have been offered $100.00 for it and the 5-6 lb. Fiji rock its attached to!