Hey there, when i started my tank i had 3 FD's then one day the tops had pop off, i was sad. I had ask this guy at the store what to do, he said that how the reproduce. Darn if he wasn't right. Now i have so many in my tank its unreal. they were growing in the overflows,sump everywhere . I most have atleast 35- 40 now their not real big but they are growing. So just give it a few weeks and they should start to show.