not trying to sound negative already but the mandarinfish u have and the blue link star fish u have are definitely not going to live.1 the mandarin dosent have enough food in the tank to survive some thing like live cyclopees is the main thing he need and u dont have any in the tank and the blue star dosent have anything to feed on either and it will slowly die off I have learned this from experience.I do have a really good secret to keep the mandarin to live red or brown flat worms are awesome for that little guy but there nothing that u can buy I lucked out on this info from a really close freind of mine that knows alot about reef tanks and saltwater fish.I would take the madarin back to the store if I was u and get something else in his place ntil u can supply enough live food in your tank for him to survive,I can see he is underweieght not a good sign. I just dont want to see u envest all your money in this guy only for him to die also take back the star fish until later on.If u want go check out my profile and see my tank,any questions I would love to help.=)