If you provide lots of fine leaved plants for cover and the trio is well fed, you will have plenty of survivors from each drop to quickly fill your tank with fry. Not all of the fry will make it but the number of survivors will be large. I keep a colony that breed freely in a 10 gallon and I sell a dozen or so from that tank every few months without ever seeing a reduction in the population. Whenever they look a bit crowded, I just scoop out 8 or 10 adults and sell them at a club auction.