Clown missing fin?

[Saratj1]

Have a small clownfish that appears to be missing its top front fin ( I dont know the proper name of this fin) is this normal? The fish seems fine eats and messes around with a saltwater mollie easily enough. Is it supposed to be like that? Is it a birth defect? I'm just curious thanks in advance.

Here's some pics.

 

[Hocky puck]

It will grow in very pretty fish very vibrant