not knowing a thing about cycling (when i started, i figured you filled the tank with water, set up your decor, put the filter in, turned it one and letting it sit a month like that would make it all good, sheesh), i put about 10 fish in to start. five died, two i returned to the store (they were guppies and looked so fragile at that point that i didn'twant them to die too), and three (a molly who i still have and two platies that have since gone on to live in someone else's tank) survived new tank syndrome (you don't mess with Big Momma the molly, she's one tough cookie, and grew quite large actually)