Looks like a fawn, possibly a beige. It's hard to tell before they molt.

Keep in mind that high whites are at risk for megacolon. I'd breed him/her to selfs, hoodeds, etc. It's a horrifying experience dealing with an entire litter of megacolon babies. They aren't even worth feeding off as they aren't digesting their foods correctly.

Either way, very cute little guy. I've been working with masked rats lately, and I'd love a fawn masked rattie. I've never actually seen one before.