Q: Is it possible that a spawn of 70 fry could all be female?

Question submitted by Melynda, Shasta Lake - CA

A:  Well Melynda, the only thing I am actually 100% sure is that when it comes to bettas ANYTHING is possible !!!!  LOL

How can such great

So logic may assume that in a spawn of 70 fry you have 70 times the opportunity to produce a male. Human logic, that is. Betta logic however is quite different. There has been much speculations as to why spawns sometimes yield mostly males or females. Many theories have been presented, none of which substantiated, and to mention but a few: water PH, age of the breeders, zodiac sign of owner (just kidding) LOL. The truth is that we really do not have a clue as to why some spawns are female heavy or male heavy. So is it possible that an entire spawn yield only one sex? Unlikely, yes, impossible, no.

In my personal experience, I have seen smaller spawns yield only one female, but have never had an entire spawn just one sex. So here are a couple of things to consider:

  • Are your fry under 6 weeks? It is oftentimes impossible to tell males and females apart at first. If your spawn is young (under 6 weeks) chances are they all look alike, short finned and pretty much 'female like'.

  • Are your fry over 6 weeks? Around the second months, the males will start growing fins and differentiating themselves from the females. Eggs spots on females will be easier to spot, too. But some males take their time and this is especially true of some halfmoon strains. I once had a spawn of Blue moons that yielded over 60% of true halfmoon. But the males took forever to grow fins. Their bodies was big but they all looked like females. At about 3 months old I was sure all I had was girls. When suddenly POOF, the males went into blooming mode and within a couple weeks started growing fins.

  • Different strains mature differently. As I was saying just a second ago, some halfmoon strains may take longer to grow fins. In comparison for example, my Apache males seem to grow fins real fast. Their bodies might still be small, while their fins are already long. So no way to confuse them with their sisters :).

Spawns that are out of balance sex wise can cause some logistics problems. An all female spawn may be easy to deal with since you can pretty much keep all the gals together in one large tanks, for a fairly long while. On the other end, an all male spawn may be enough to drive a breeder to the brinks of insanity. One may not be prepared and be short of jars, or shelf space. Suddenly there are jars and bettas everywhere, bathroom, kitchen, bedrooms, library, etc :))... Divorces usually promptly follow LOL.

Well, goodluck with your (possible) betta harem, but like I said, if they are still young, you very well have quite a few males in the bunch, they just haven't popped up yet :). Goodluck :).