You dont need VBA for this. Your range  is in B1:B6. Conditional
formatting of cell  B1: choose
'Formula is:' and enter this:

=B1=SMALL($B$1:$B$6,COUNTIF($B$1:$B$6,"<=0")+1)

and set how you want it to be highlighted. Then using the Format
Painter icon on the Standard Toolbar, copy to B2:B6.

This excludes negative numbers as well as zeroes.