i agree with wasp 5 fish in a 30L tank is to much
in regards to a skimmer im setting up a 54 L nano and im using this http://www.redseafish.com/Product.asp?d ... &proID=121 (Berlin Air-Lift 60)
yes its just a air powered skimmer but can be used in a tank up to 240 L so it should work well in a 54L tank :-?