About a month or two ago, I separated out a pair of F1 Betta sp. cf. rutilans green from the others, and put them into a smaller 'breeding' tank. This pair has somehow managed to successfully spawn in the main tank, and the poor male with his mouthful of eggs was being constantly harassed by his siblings.
To be honest, I never expected this experiment to result in viable fry. Not only were the breeding pair well over a year old (probably closer to 24 months), but past treatments with some rather harsh chemicals made me wonder if they would even be capable of producing fertile eggs. Surprisingly, the very next spawn resulted in fry, as did the several successful spawning attempts that followed.
Because I wanted only a small number of fry to work with, it wasn't long before the pair was moved back to the main tank, and my attention turned to raising the dozen or so fry left behind in the breeding tank.
As you can see from the photos, some of the fry are more developed than others. There is one particularly small fry, who somehow holds its own against older siblings, in spite of not being much bigger than the grindal worms I put in for them.
My main concern was that this group of fry would be infected with oodinium through their parents. However, at this point in time, they seem as physically healthy as any of my other fry, and I doubt it's going to be all that long before they outgrow their current tank.
This species seems to have a particularly aggressive streak, and I'm already seeing aggressive posturing and chasing between some of the bigger fry. Based on my experience with the F1 group, and even the F0 pair, a steady increase in aggressive behaviour is to be expected, particularly as the fish reach sexual maturity.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.