help me please.

Question
I have 3 angelfish in a 10L tank. (the man at the pet store said this would be
ok) they are all pretty small fish. the water is ammonia and nitrate free and I
have had it tested at the pet store and the ph etc is normal.

they are all swimming vertically. one of them is eating the other is eating and
then spitting out the food. the other is not eating at all

I have only had them for 24hours and already one has died. (the one that
wasnt eating) I followed all the practices that the pet store told me too and
the fish were swimming happily whilst at the pet store.

i have another tank with 3 happy and healthy black moors.

why are my angelfish swimming vertical and at the surface?

I am afraid they will die overnight

i cant understand what I am doing wrong please help!!

I wont the 2 alive angelfish to live!!  

Answer
Hello,
I am sorry to go against what you have been told, but angelfish need at least a 20 gallon tank to do well in my experience. I am also sorry to inform you that your test results are wrong. With 3 angelfish (which happen to be very "messy" animals) in a tank that small, I can almost guarantee you have problems with Ammonia, Nitrates, or Nitrites. The stress associated with transportation and the newer, smaller environment can also prove fatal to captive rased angelfish, as they usually (not always, but this is a problem unless you special order them from a reputable breeder) have week genes.