Neons, the "recipe" above is flawed in many respects, difficult to know where to start in fact. Neons are not an easy fish to breed, rather they are, but the conditions required are difficult to maintain. They require almost no hardness in the water for the eggs to hatch, and such water is very unstable.
The fry when they emerge after around 24 hours will be consuming their egg sac and do not require feeding until free swimming, after 5-7 days, adding food earlier will pollute the tank and kill the fry. Infusoria or a good quality liquid food is essential, BBS are, as posted above, FAR to large. The original author of that description has not bred Neons.
Guppies, just add water and wait.