Are you going to buy a tank of already have one that you are going to convert? The size of the tank will make a difference on the type of fish you can or can't have. Are you going to have a reef tank? That will help determine the fish you can have as well, some fish eat corals. What type of cuc are you wanting if any? Any invertebrates you are wanting? Remember the order you put your fish in may make a difference in what fish you can keep together.
Two things you will need is a refractometer and a test kit when you first begin.
It is always best to your ro
water from day one to help cut back on the algae.
The light will be the most important thing when keeping anemones and corals.
Take your time only bad things happen fast in saltwater.
This is decent site to use for checking out sw
fish Saltwater Fish: Marine Aquarium Fish for Saltwater Aquariums