Since no much useful information on the web about it, here I am writing my breeding report.
The male guards eggs. I moved about 30 eggs to a 20 gallon planted tank. The female actually laid more than 120 eggs in total during a period of 3-4 weeks. The rest of eggs in a community tank probably won't survive, especially there are blue rams, dwarf gourami, and betta who will search for fry.
I put eggs in a breeding net across the out-let of filter. This can oxygenates the eggs. The hatched fry are tiny, they can even go through the breeding net, while zebra danio fry can't go through it, even zebra danio eggs are a bit smaller than Florida flag fish's eggs. A sponge is needed to cover the filter in-let, else, the fry will be ended in the filter. The breeding net is not necessary if no predator in the tank.
The fry stay at bottom without much movement for 3 days. Then they will dart around at the bottom for another 2-3 weeks. They can't swim well. I find the survive rate has nothing to do with deep water or shallow water as someone else described about that the fry need to get air at the very beginning of hatch as this is easier when they are in the shallow water. My tank is 13" high from substrate to water surface and presumly this is deep water, but almost all of them survive well.
No food were provided for them as they are too small to eat FirstBite or baby brine shrimp in the first 2 weeks. However, the planted tank is recommended as this will keep water clean and also provides micro-organism for the fry. The tank contains several red cherry shrimps. In one week, several Apple snails were added in the tank. Snails poop is bacteria and micro-organism rich and is good food source for the fry. In the second week, I added a tiny bit of Hikari FirstBite or daphnia once every day but I don't know they can eat it or not.
In the third week, you can see them dart around more in the tank, grow a bit bigger and look close to a newly-born guppy fry. They still need stay on bottom or plant/rock/driftwood surface most of time, not like livebearers or zebra danio fry who can swim continuously in the water very well. But they can swim to catch food in the water column now. So, I am going to provide live baby brine shrimp for them to practice.
If you keep water clean (my tank NO3
< 5ppm), planted, no predator, almost all eggs can be hatched and all fry can be survived.
My initial batch of fry were lost when follow someone's instruction (in a gallon bowl with green water but without filter) - either due to high temperature from sunshine or some unexpected predator from local pond, but the second batch are all growing well and I think they passed the 'risk' stage. I also think when they are 6-weeks-old, they will be big enough so that I can move them to the community tank.