I actually just posted about feeding in another post, but I'll repeat part of it here.
I got this one at around 4" and fed it mostly blackworm until it was around 9-10"
I then switched it to pellets (Masivore/Algae wafers)
Once it hit 18" I added talapia chunks to it's diet, mostly because talapia is cheap protein.
I think pellet food is very important for these fish. In the wild they reportedly eat a lot of Mollusks, so that means they are also eating the gut contents of their prey, which would be algae and vegetable matter.
When fed a lot of pellets it really looks it's best, it actually gets a rosy color on the lower parts of its head.
I also think the algae wafers do a lot to combat lateral line erosion, other members have noticed this as well.