Why won't my African dwarf frog eat?

About a week ago I got an ADF and I was super exited.Unforty he won't eat or swim around.My brothers does so I'm getting worried about him. I put freeze dried bloodworms in there but I havent once seen him swim to the top and eat one yet. Will he live?is this normal?Will he do it if I turn the light off?Thanks for any suggustions.