males or females

[Jason]

I am a happy ownner of about 15 little Apistogramma cacaduoides. They are about 10 weeks old and getting bigger and bigger... except they all look the same...it seems they are all females. How early can one tell females from males, would I see males at this stage if I had them?
Jason

 

[farm41]

They may surprise you still, it's kind of early to tell.

 

[Jason]

Thank you.

 

[Z Man]

At a very small size sometimes you may find some of the juveniles has a black front edge to their ventral fins. Those are females. Without the black edge are male. Only time will tell some times.

 

[R-S]

Is the black edge to the ventrals a firm female-only characteristic in juvenile cacatuoides (double/triple reds)? If so, then I have maybe 5 out of 27 that are male, and they are growing significantly slower than the females. :?

I've read the posts and several articles on the possible effect of pH on sex with interest and was wondering what my mix would be, given that they were spawned in 7.4 and have grown out in 7.8.

Since most of mine are under 1", I was hoping that some late-blooming males would show up as they grew. Daddy of the batch died and I am really hoping for a fine specimen from this batch to replace him, but now I'm thinking that the odds of this are pretty low if only the little runty ones are the males.

 

[Jason]

Dear Z-Man,
please, please be mistaken! They all have some black coloration on their ventral fins! There are a few though that have only a tiny trace of black...Like R-S's, the male-father of the fry died last week, what a disappointment it would be not to have any males among his offsprings!

 

[Jason]

Dear Z-man,
You were not mistaken, all of my fry showed black coloration on their ventral fins and there is no doubt now that they are all females. I know the sex of Apistos is determined by the temperature in which the eggs are hatching. So what is the magic temperature at which there would be about 50% ratio of males vs females?
Jason

 

[aspen]

>>'I know the sex of Apistos is determined by the temperature in which the eggs are hatching. '

i'm not sure that you KNOW that, just that it is a tendancy of some cichlids to be more of one or the other, depending on temp, and/or ph. there are liklely more factors to be considered. one person proved that the largest of the bunch of one species were males, even when he separated the bunch, large and small at a young age. 1/2 of the small group were males, as were 1/2 of the larger group, but the larger of both groups were males.

this is an interesting topic.

rick

 

[R-S]

This is an interesting topic to me too. With my cacs., all of the largest in the spawn are female, without doubt, unless males can assume such female coloration as to be bright yellow when excited (feeding white worms gets half the tank yellowed up!) and have the black ventral fin/lack of tail & dorsal markings like a true female. That's not possible, is it?

I can clearly identify 3 males of my 27 fry, with a couple that are still so small as to be able to go either way.

My spawning temp was 80F and they are growing out in 78F. I've never heard of the temperature being a prime factor. Hm.

 

[Jason]

It is very interesting indeed. I have my fish in about 75 - 76F, did not change it since before the spawning.
Hopefully I will find a male soon and then will try to experiment a little with the water parameters.
Jason

 

[Z Man]

At "just under" and inch (2.5cm) it shoud be very obvious what you have. I have found that the black ventral is an excellent indication of females. But also at that size, the males should be at least starting the 'lyretail' design. As far as sex ratio; I really don't know as I have never even done tests on water pH or temperature as I am mostly interested in getting ANY fry. They are great fun to watch.

 

[apistodave]

Temp is THE most significant factor though there are others. You need to get Romers Atlas, he has studied this extensively and their are tables in itthat are species specific.The magic temp is in there!