Inch per gallon rule is pure bunk. It may have served as a guideline for most beginners but this is easily misinterpreted and does not consider the size, temperament and many other variables of the fish. Imagine someone keeping a 10" oscar in a 10g tank because of this rule. .
I'm awars of that, that's why I said rough rule
, especially since I knew namora was talking about guppies and tetras. I know that a full size oscar in a ten gallon wouldn't work, or 3 bettas in a 10 gallon etc.
"Everyman dies, not every man truly lives." - William Wallace