Every single one of my past spawns, has been considerably male-heavy. I'd probably estimate that for every two or three males, I'd be lucky to get even a single female.
Unfortunately, because most hobbyists only want to buy breeding pairs or trios of fish, such a heavily skewed sex ratio can make it difficult to move on surplus males.
As this had been my experience with previous spawns, I was expecting to see much of the same when I got my new stock in towards the end of last year.
Surprisingly, the reverse seems to have happened.
Both my Betta sp. apiapi and Betta hendra pairs seem to have thrown almost all females from consecutive spawns. Understandably, this could change because many of the fish are only young and haven't fully coloured up. But based on my current assessments, I would not be surprised if I only had a couple of males present in each group. I also have a number of juveniles in my Betta brownorum tank that still haven't been correctly sexed, so I will be eager to see if this trend continues.
What I am particularly interested in, is finding out what environmental factors have influenced this sudden shift. I have made some recent changes in my husbandry practices, such as maintaining a slightly cooler water temperature, and easing back on the frequency of water changes. I also started using aqua soil as the substrate in all my tanks, and I am wondering what effect this is having on the pH (if any).
I'm hoping to purchase a digital pH meter in the next couple of weeks along with KH and GH test kits, so that I can get a more precise picture of what is going on with my water. It would be great if in the future, I could manipulate the conditions in my tanks to provide a sex ratio as close as possible to 50:50.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.