These are my personal acessments about your thread.
1) How was you able to cycle your tank in a week? What let you know it was cycled?
2) A starfish needs a very mature and stable tank which usually takes about 6 to 8 months, longer for a starfish that size. Starfish go around the tank feeding on microbes. That size star needs to be in a much much larger tank.
3) If you do have a tang or a butterfly fish any research at all would have let you know that it can not be in a 10 gallon tank.
4) As far as the sea fan it`s going to need plenty of plankton. Enough that your ten gallon tank will get quite fouled up with excessive nutrients causing algea problems. I dont know what kind of lighting or flow you have but it needs to be moderate to high on both of them.
In retrospect, I`m not trying to mean or anything like that but you said earlier " I just setup a 10gallon salt water tank. Yes i know 10 gallon is a bad idea but i have no choice." I really disagree with your statement. You do have a choice. Your other choice would have been to say, Hey these inverts and fish are not going to make it in that size tank so let me wait till I can do things right. Not to sit their and say I`m going to do it anyway no matter how my tankmates suffer. I know it looks nice now but a yr from now I would say not. Like I said I`m not being ugly but a little research goes a long way. Also I`m NOT saying in no way that you cant have a 10 gallon SW
tank or even Reef tank. There are many people that do but their inhabitants of those tanks are compatible to that size tank. Dont take this as negative critisism but a chance to say lets research this out and find out what we can do.