after throughing a number of $ because of dead fish because of not cycleing my first freshwater tank, the longer it cycles, the better.. I threw a very unhardy fish that I had purchased that same day into a 30 gallon tank, that is when I was done filling it up with water... PLus the fish waited in a 2 hour drive home..... I was amazed when it did not die after puting it in... Then I went to walmart and bought 6 different fish, brought them home, and watched my luck run out.....