Flagtail Prochilodus feeding?

What do you guys feed your Flagtails?

I've had him about 3 days doesn't seem to be interested in Hikari algae wafers, cobalt spirulina flakes or pellets. He's about 4.5" great coloration activity and has no problem grazing on tank algae. Aside from the what should be expected, not going after any of the carnivorous foods either.

Looks like I might have to try some NLS. I've been a solid Cobalt and Hikari fan boy as far as food goes!
He also has no problem munching on the plants in the tank. Which is fine they are primarily a side food for my SD's and he took right to schooling with them so I guess he learned from example.
This is the first fish I've ever picked up that didn't accept any food after the first 24 hrs which is why I was a looking for what other Flagtail owners feed. I've wanted one for a while and just got adequate housing setup to finally grow one out for life.

I wanted to try to stay away from blanched greens as a staple the only vegetables I like to feed because of ease of prep work are cucumbers for my panaque which is like a once or twice a week treat. Will have to get some in there today or tomorrow but usually my panaque is like a hawk and devours them in minutes.