I will say after keeping Neos for a couple of years now. It took me finally keeping them on their own with zero fish to finally have that shrimp explosion. I could def get babies with some fish in the tank (rock pile and some heavy cover spots allow for this, but you don't realize how many are likely getting picked off until you try them in their own tank. I will second the comment above about having a mature aquarium. That is very important as well. The third and final thing I'll mention is when I had them in a tank with a substantial snail population, they never did as well as I thought they would. They would reproduce and expand, but never quite thrived. I once saw someone say that while they can easily co-exist, its tough for both populations to thrive together. In the breeding set up I have now, they are many snails, but I would say the shrimp are thriving and the snails are just kind of getting by. I don't know if there is anything to it or not, but I think my ideal setup now if possible would be only with nerites or mystery snails where I could easily control the snail population. Good luck!