Originally, I used to let my wild betta fry live alongside their parents. They would feed off infusoria and whatever other micro-organisms they could find when they were small, and wean themselves over onto the food their parents were eating once big enough.
While this method worked, I would only end up with perhaps one or two fish surviving from each spawn. Because this complex seems to skew towards male dominant spawns, such a small number of fish surviving through to adulthood meant it could be quite difficult to continue with a line beyond that first generation.
I then had the idea to use separate grow-outs such as those used by breeders of Betta splendens. This meant fry from cannibalistic parents were protected, and the diminished competition for food meant that the survival rate was much higher. However, I found water quality became more of an issue due to the larger number of fry in these grow-outs and the uneaten food left after each feeding.
Unfortunately, I chose to use this method when nearly all of my stock was infected with velvet - including the fry. The effort of trying (and usually failing) to treat so many fish in multiple tanks was exhausting, and by the time I had purchased my three new pairs from JotyaBettas, I just wanted this hobby to be as stress-free as possible.
I still think leaving fry in with their parents with minimal intervention - at present I do provide fry with BBS, microworms, and small mosquito larvae - produces a more robust fish. I don't push for fast growth. Instead I let my fry mature at their own rate. My interest is in producing healthy fish, and if that takes close to a year to achieve that is fine by me.
The fry from my three newest pairs (Betta hendra, Betta sp. apiapi and Betta brownorum) are thriving in this set-up, and I'm hoping that I'll be able to use the same method with fry from subsequent pairs.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.