Congratulations on your new seahorse.
There are captive bred seahorses showing up more and more these days at the wholesalers, so there is a good chance she is captive bred. The fact that she is eating frozen mysis is also a good indicator that she is captive bred. Most wild caughts will not without quite a bit of effort.
You will see quarantine times of anywhere from 2 weeks to 6 weeks depending on where you are reading. I personally like and use 6 weeks myself.
Best of luck with your newest addition.