Feed him several times per day. At least three times a day until he’s a foot long or so. I feed Hikari Jumbo Carnisticks and Fluval Bug Bite sticks for turtles. At that size the regular Hikari sticks will be easier for the fish to take and if he already eats them, load him up.
I feed a bunch of other stuff as well ( like shrimp) but as a primary staple the Hikari and Fluval seem to work well for me and they’re amazingly convenient. Most other fish in my tanks like the same feed.