Hi there. We have two salt water tanks that we have had and maintained for over a year now. I started watching a ton of YouTube videos as we were getting into the hobby and expanding our salt water fish selection. One of the websites that kept coming up was this one:
https://m.liveaquaria.com/divers-den.
They have live fish that you can purchase and have delivered to your house. We have not actually bought any fish from them because the shipping was quite expensive for us, but it may not be as bad for you. They are who I would check out if I were looking for a particular fish that I couldn't find at our nearest pet store.