First GM animal sold in US will probably be Salmon!

The smaller fish is a natural fish, the bigger the GM fish of the same age

Yep, the first GM creature to be offered for sale will likely be Salmon - as far as I can see the decision isn't finished yet, but the press seem to be pushing the idea that it's likely to be a yes.
I looked on AquaBounty's & it seems the decision hasn't been reached yet (you can keep an eye on developments here).

Here's an article by Doctor Greger. If you want to check it out more online, just google AquAdvantage Salmon