Male guppy missing pectoral fin.

HI there,
I'm adding this question for my friend who has been setting there tank up along side me.

She went to get her new fish today 2 of them male guppys . One looks stunning and no issues. The other when she got it home noticed it's missing it's pectoral fin. It looks like a little stub with a darker tip.

Before she adds this to her tank the question is what could this be? It doesn't look like fin rot. The rest of the fish looks in great shape.
Could this grow back? Could it be from an aggressive tank mate at the store?

Thanks in advance.

 

I'm not sure if it would grow back. It's possible it's an injury or a birth defect. Do you have a pic? Does it swim ok, is it active and chasing down food?

 

Yes I will attach. I think I started a new thread by accident too.

Hes happy healthy eating swimming she won't be adding him to the tank. He's in qt for now.

 

The blue guy. Little black spot is a stub

 

It certainly doesn't appear skinny so it seems he can compete for food but I would still keep an eye out in case he gets bullied as well.

 

Should I let her know he's safe to put in the main tank? He does seam supper happy when I was there.

 

What else is in the tank and how big is it?

 

El337 sorry been busy, but she's got a 40 or 45. We took it back to the store to get a new guy just in case.

Other fish I could be wrong and not many yet.

2 snails.
2 guppys
2 vamp shrimp
A pair of German Rams

 

That was probably a good move to take it back.