Welcome to 3 reef!
I also have a 55gal. It's been reef for 10 months, but I've had it for 4 years. As to what you want to keep coral wise what type of lighting do you have? Reply and we'll go from there.
For fish 2 clowns are ok and even the flame angel, just be warned that out of all of the pygmy angels flames are one of the hardest to keep. And stick to the one pair of clowns. It's never a good idea to put 2 pairs together in a tank together unless it's massive. Just because it's been done doesn't mean it should be. As far as tangs go I always tell people flat out "no" when it comes to a 55. Sure you could get a baby and have it until it grew some but then it would have to get rehomed so you would need to make sure you had someone in mind with a bigger tank that could take it or a
reliable LFS to trade it in at.
Instead of a tang try a wrasse. There are many reef safe beautiful wrasses to choose from for a 55. Try one of the fairy or flasher wrasses after your tank has had time to establish itself. I'm assuming you know about the cycling period (which will probably start over when you add that extra 20 ibs of rock). Don't add fish to quickly, and always know your water params before you bring something new home.
Since this is your first SW let me save you some heartache. DO NOT bring something home that you have not planned on getting or know the requirements for (feeding, light, temp, etc.). LFS advice that you're getting the fish at does not count. Most of them will tell you anything to get the fish sold (Not all, but most).
As to your beginner corals, once again I need to know your lighting situation but normally any SW tank can have zoas and mushrooms, both of which are very easy to keep.
For a clean up crew, besides a lawnmower blenny or foxface (venomous
) for a cool algae animal (both are fish) try some snails. Mexican turbos are my favorite. They're like lawnmowers for your tank and they do a lot of work for one snail so you won't have to go nuts with them like a lot of people have to with other snails. They can be clumsy, but they're well worth that IMO. Nassarius snails are great for the sand bed.
Keep in mind that anemones need lots of lighting so once again we need to know what you have first.
Good luck and feel free to ask questions anytime.
