Male dog picking up puppy?

Your dog was probably confused by the puppy.Many dogs aren't quite sure what a tiny pup even is for sure. LOL He most likely was not being aggressive but rather playing or 'exploring' -- unfortunately a lot of times this is rooted in prey instinct and can often turn into trouble even if it starts out innocently enough. But, I wouldn't worry too much about it... he was calm enough, and as the puppy grows this will be less of an issue. Just make an effort to get them accustomed to each other and set the boundaries with good obedience, and things will probably work out just fine.