Concerns for new clownfish?

I just got a new clownfish the other day. I know it's a bit early to tell but this is my first saltwater fish and I do have a few concerns and questions.

He's a very tiny clown, about 3/4 of an inch long. Is it likely he is still male? I wanted to try and pair him with my larger clown (1.75") who is being shipped to my LFS and should arrive in a few days.

He keeps opening and closing his mouth. He's not gasping for air exactly, just kind of opening and closing his mouth as he swims like a goldfish might. While in on the subject of swimming I might as well mention that he's acclimated rather quickly and swims all over the tank! It's like he never stops! I've also seen no signs of fin clamping. He even ate a bit of mysis shrimp last night before the hermit crabs got the rest.

My last concern is his dorsal fin. Like I said, no signs of clamping but the very front of it is white. That may be his color as he is a fancy snowflake clownfish, not a standard ocellaris. Any opinions on that would be appreciated, thanks!