Hello, I'm new to owning a salt water tank (and new to this community) as I just bought my 15g biocube (or maybe it's a nanocube? they look the same to me) a week ago. At my lfs, they told me they would set up my fish tank for me. A week later I came home with a cow fish, two percs, and an anemone. However, this morning I noticed my cow fish has white spots that he never had before. Also, one of my percs was fading in color. My friend went and bought me Instant Ocean: Lifeguard but I am unsure if I should use it since it's still a new tank and I'm unsure if it would harm my anemone. Also, since I did not set up the tank myself, I am unsure about the UV sterilizer. I'm sure I don't have one when I looked up what they looked like. I also had to look up what my carbon filter looked like as well. So please, any help to save my fishes would be really appreciated, thanks!