I am currently breeding Melanotaenia praecox (dwarf neon 'bows)
Im am doing it exactly as caserole stated, and I agree with the statement that spawning is easy, and raising fry is not so easy.
temp is about 26-27 degrees and water changes are done with cold water which makes the go nuts and spawn
due to the small size of the fry they need microscopic foods.
I use green water, liquifry #1 , micro worms, and keep adult daphnia in with the fry. The bigger fry feed on the newly hatched daphnia.
The fry grow very slowly