steel blue

[fishgeek]

anyone any experience on whether these are harem spawners or form permanent pairs


andrew

 

[Mike Wise]

Most regani-group species breed in pairs, but if given the chance the males will often breed with several females.

 

[fishgeek]

another question, do we know why the sex ratio in these comes out so skewed
i have only one femal from about 30 fish so far!! bred at 24-25 celsius and 5.5-6.0 pH

andrew

 

[Mike Wise]

Papers by Römer & Beisenherz indicate that 26º should give a sex ratio closer to 50/50. At lower temperatures A. caetei (& I suppose species close to it like this caetei x resticulosa-complex form) produces more males. Other apisto species at this temperature produce more females. They don't explain the reason for this. If I were you I would raise the temperature to 26-27º & see what happens. The low number of females is common for this form. Maybe it is a genetic problem & not a temperature effect.

 

[Apistomaster]

Mike,
While hardly scientific the first time I bred a pair of wild caught blue-white aggies was in Seattle during the "summer" and I chose not to use a heater. The water temp happened to be about 26C and I ended up as close to 50/50 at maturity and 80 fish, I was amazed because up 'til then all that I had read led be to expect mostly males.
All this has already been discussed in the forum. Can you point me in the right direction for me to catch up?
Thanks,
Larry

 

[Mike Wise]

Here is one discussion on the topic: http://www.forum.apistogramma.com/showthread.php?t=4149&highlight=ratios.
If you go to the top of this page, click "Search", and enter "sex ratio", you will find many more. I once had a spawn of A. agassizii (101 raised to adults). All turned out to be females. The parents spawned in late September & I left the window in the fish room open. The tank they were in stayed around 72ºF/22ºC.

 

[Apistomaster]

Mike,
Thanks for the directions. Go figure over a 100 with 1 or no opposites. As bad as the killies especially Nothos. Bottom line is I guess we don't know for sure why this happens.

 

[Mike Wise]

Apparently temperature is very important. According to Römer, dominant females in the wild pick areas where the temperature is closest to 79ºF/26ºC. Their offspring tended to be 50/50. Subdominant females, who spawned in deeper (cooler) & shallower (warmer) waters had skewed sex ratios. It seems that in this way the dominant fish were guarenteed offspring of both sexes & increasing their chance of providing their genes to the gene pool, while subdominant fish supplied mostly 1 sex, with less genetic input into the gene pool. It seems they know more about genetics than most people.:wink:

 

[Zapisto]

they finally found female of theese fish ?
hahah