Too many females

[gwand]

The last spawn for my a. cacatuoides was on July 3rd. It looks like most of the 20 juveniles, except one, are females. The breeding pair were kept at 78F and a pH of 7.0. What can cause this lopsided sex ratio? In another tank, my endlers and sailfin Molly are producing only females too. It is hard to rehome the less colorful females. How can I manipulate the sex ratio.

 

[GaryE]

The great mysteries...

Some serious German aquarists did a study 25 years ago and concluded that 26.5 all through the early life process could give more even sex ratios with dwarf cichlids. That was a vague conclusion, since the group is large and not just on one continent. But it has been a good guideline here, with some fish.

I have the opposite with my Parananochromis, and they would die at 26.5, so that the research had its limitations. My fish weren't in the hobby back then. But with Pelvicachromis, I've hit 50/50 at that temp.

I've seen experienced aquarists raise 50 or 60 young Apistogramma and never get a male.

 

[gwand]

Wow. I’ll stop breeding these fish if I cannot correct the ratio.

 

[emeraldking]

Young Apistogrammas look like female. I've kept and bred some Apistogramma species myself in the past. It took months before I saw male traits developing. But I've kept them at 24°C all the time.

In most ovoviviparous livebearers there are two reasons why only females will be born. If the father is an XX male instead of an XY male. A XX male has an autosomal locus with two alleles, a and a. While a female has got an autosomal locus with the alleles, A and A.
An XX male crossed to an XX female can only reproduce females. So, this has got a genetic reason why only females will be born.
If it's an XY male crossed to an XX female, both sexes can be born. But if you keep them at 24 °C and higher all the time during the whole pregnancy (later on has no effect), more males (till even just males) will be born. Between 22°C-23°C, both sexes should be in there. At lower rates, more females will be born. This is not a 100% guarantee but most of the time it works.

I've deliberately mentioned: During the whole pregnancy. For when they're not pregnant, a different temperature could be used. For if you keep them at the same temperature all the time (so also when they're not pregnant), both sexes will be born at some point. For it's actually the temperature regulation during pregnancy (putting it higher or lower) that makes the difference in comparison to the normal water temperature to get more of one certain sex in the offspring.

The only species that this process works the other way around is in superfetative dwarf livebearers such as Heterandria formosa, Neoheterandria elegans, Quintana atrizona, Phallichthys tico and Carlgubbsia kidderi. Lowering thetemperature during the whole pregnancy results in more male. At higher water temperatures during pregnancy, more females will be born.

While your water temperature is higher, the water temperature trick isn't of any worth in this case. Which makes me think that your males are XX males. XX males occur quite often.

Hop this may give you some more insight of how it works.

 

[gwand]

Young Apistogrammas look like female. I've kept and bred some Apistogramma species myself in the past. It took months before I saw male traits developing. But I've kept them at 24°C all the time.

In most ovoviviparous livebearers there are two reasons why only females will be born. If the father is an XX male instead of an XY male. A XX male has an autosomal locus with two alleles, a and a. While a female has got an autosomal locus with the alleles, A and A.
An XX male crossed to an XX female can only reproduce females. So, this has got a genetic reason why only females will be born.
If it's an XY male crossed to an XX female, both sexes can be born. But if you keep them at 24 °C and higher all the time during the whole pregnancy (later on has no effect), more males (till even just males) will be born. Between 22°C-23°C, both sexes should be in there. At lower rates, more females will be born. This is not a 100% guarantee but most of the time it works.

I've deliberately mentioned: During the whole pregnancy. For when they're not pregnant, a different temperature could be used. For if you keep them at the same temperature all the time (so also when they're not pregnant), both sexes will be born at some point. For it's actually the temperature regulation during pregnancy (putting it higher or lower) that makes the difference in comparison to the normal water temperature to get more of one certain sex in the offspring.

The only species that this process works the other way around is in superfetative dwarf livebearers such as Heterandria formosa, Neoheterandria elegans, Quintana atrizona, Phallichthys tico and Carlgubbsia kidderi. Lowering thetemperature during the whole pregnancy results in more male. At higher water temperatures during pregnancy, more females will be born.

While your water temperature is higher, the water temperature trick isn't of any worth in this case. Which makes me think that your males are XX males. XX males occur quite often.

Hop this may give you some more insight of how it works.

That is very helpful. Thank you. At what month of age will the Apistogramma cacatuoides show a male phenotype?

 

[Innesfan]

Skewed sex ratios, the bane of apisto, killie and livebearer fanciers. @emeraldking offers some invaluable insights.

Does the 2-to-a -vessel method work when raising Apistos? I know @GaryE hasn't had success with it with his killies but I have. And I know some guppy folk who swear by it for their problem strains. I actually use 3-to-a-vessel with the killies and wind up with trios or reverse trios reliably.

My only first-hand experience with gender issues for Apistos was a while back when I had a trio of Apistogramma nijsseni. A pair formed and spawned. The male died--or was killed. Within days the other 'female' started developing male pattern, color and size and ultimately paired off with the female that had just raised a brood.

 

[gwand]

For this spawn I had the pair in a 20 long with 10 n. beckfordi.

 

[Colin_T]

I used to breed my Apistogramma cacatuoides and Epiplaty killifish in water with a pH around 7.8. The higher pH gave me around 80% male offspring. Other people I knew who tried this also got more males in the higher pH. Wild caught fishes won't do well in the high pH but captive bred fishes are fine.
The GH of the water was soft (below 50ppm).

I never found any sex ratio differences due to water temperature and my fish were bred in temps ranging from 24-30C.

 

[GaryE]

We are in a familiar loop. We don't know.

The larvae hatch with the possibility of going either way in Apistos. The genetic possibilities are there, but they have worked out very differently with livebearers than with Apistos.
Some will argue it's genetic.
Some say pH.
Some say temperature, which has at least been studied and seems to offer something.
Possibly, it's all and or none of the above.

All we know for sure is that it's an issue. There are dark rumblings that many fish farms use methyl testosterone to solve their issues. I was once offered some in a discussion like this, by a Russian commercial Discus breeder. He injected his adult fish with hormones before he sold them, to jump up the colours, but said he had a little something to solve sex ratios with my "useless tiny fish you couldn't use a needle on". I didn't take up his offer.

If you've ever wondered why half a dozen generally linebred Apistos are all that's available regularly from a group with dozens of beautiful species, you've found the answer. Sex ratios bedevil breeders.

I once bought a full bag of 2 week old Apistogramma eunotus group fry, to raise them up carefully. All I got were females. This makes me think the period right after hatching may be crucial to hit the triggers that determine gender. it's a guess.

With West African Pelvicachromis, I have had a fair number of males among the many hundreds I've raised who were obvious males, but never became sexually active or showed any interest in courting females. They seemed to prefer dwarf cichlid video games in some sort of fish basement. So the triggers seem to be complex.

German fish person Uwe Rohmer did some work on this.

 

[MaloK]

More the density thickens, the less males you'll have...

But they are going to show off like stars and start choosing their harem and protect it...

I say let it go... Maintain clear water and good food... And enjoy them interacting...