tempature how much does it play into sexs?

[Apisto ranch]

Ok now I have read alot about how sexs or affected by the temp of the water. Ok fine but is it just while they are in the egg stage or egg wiggler stage?
I have had a couple of people tell me it works like that for the frist 3 weeks of there life. I've kept the cac Orange flash water temp at a stedy 80f/81f . Even getting up ever other hr. to insure it was at this temp for the last 6 days.

So should I keep up the water temp setting til the end of the 3 weeks?

Are should there sex already set in them?

I know I'm new to the breeding game but for some reason that just don't sound right. { I COULD BE WRONG}

 

[Mike Wise]

You definitely should read the section of Römer's Atlas dealing with sex ratios & temperature. Basically, temperature at the time of spawning is not important - nor the time until they hatch. Only after hatching should the temperature be kept at a relatively steady 79ºF/26ºC for the next 4 - 6 weeks. It is this time interval that 'sets' the sex in the fish.

Ideally apistos should be kept at ~75ºF/25ºC for regular maintenance, spawned & the eggs hatched at 82ºF/28ºC, and the fry raised at 79ºF/26ºC for the first few months. At the lower temperatures the fish will live longer. A high spawning temperature gets the fish in a breeding mood. The same hatching temperature speeds up the time that the eggs hatch & lessens the chance of losing them (There are some species from cooler waters where this is not a good idea. The eggs develop so fast that the resulting fry are too small & unable to eat normal apisto fry foods.). After the eggs hatch the temperature should be set to provide the sex ratio desired. The fry grow faster at higher temperatures, too. Once they have some size, it is time to lower the fry's temperature down to maintenace levels again.

Personally, this is too labor intensive for me (I'm a lazy slug!), so I keep the temperature around 79ºF/26ºC all of the time. It is a good compromise.

 

[aspen]

>>'You definitely should read the section of Römer's Atlas dealing with sex ratios & temperature.'

romers book is an excellent book concerning many aspects of keeping apistos. you will definately gain the knowledge to keep your pairs alive and breeding, which will more than pay for the cost of the book.

rick

 

[Apisto ranch]

I live so far out of town that getting the book delivere to me is almost a no way type deal. I had it ordered but it never maded it. I called the post office and they told me I'd have to pay for a specail delivery. That it's self was double the prices of the book.
I ordered it throw Brans and nobble but it's going to take 6 to 8 weeks before it gets here. Thats one of the bad parts about living outside the normal. In this neck of the woods.

 

[blueblue]

Mike:

1. I notice that pH also affects the sex ratio, do you have some comments on it?

2. For temperature, i have also read Romer's findings and have tried by myself. As i remember, Romer's theory is based on a study on Panda...
After some observations, my current conclusion is: It depends on the species.
The following shows my own findings:

UNDER THE SAME pH VALUE (~5.5-6.0):
1. For Panda, Inka, bita, Mendezi, Hongsloi, viejtie, gephra, triple-strips, mamore, and Aggie: a higher temperature implies a higher male ratio (Romer's theory applies).

2. For dilpo and Eliza: a high temperature can yield more female than male,
and the female ratio surprisingly increases with temperature (from 24C - 30C)!! At 30C, in a batch of diplo fry, i have got 90% female and 10% male!!

As a remark, of course, my findings are NOT done in a very-well controlled environment, and so more experiments and observations should be collected
before a solid claim can be made.

You definitely should read the section of Römer's Atlas dealing with sex ratios & temperature. Basically, temperature at the time of spawning is not important - nor the time until they hatch. Only after hatching should the temperature be kept at a relatively steady 79ºF/26ºC for the next 4 - 6 weeks. It is this time interval that 'sets' the sex in the fish.

Ideally apistos should be kept at ~75ºF/25ºC for regular maintenance, spawned & the eggs hatched at 82ºF/28ºC, and the fry raised at 79ºF/26ºC for the first few months. At the lower temperatures the fish will live longer. A high spawning temperature gets the fish in a breeding mood. The same hatching temperature speeds up the time that the eggs hatch & lessens the chance of losing them (There are some species from cooler waters where this is not a good idea. The eggs develop so fast that the resulting fry are too small & unable to eat normal apisto fry foods.). After the eggs hatch the temperature should be set to provide the sex ratio desired. The fry grow faster at higher temperatures, too. Once they have some size, it is time to lower the fry's temperature down to maintenace levels again.

Personally, this is too labor intensive for me (I'm a lazy slug!), so I keep the temperature around 79ºF/26ºC all of the time. It is a good compromise.

 

[Zapisto]

very interresting reading.

Blueblue ,
you result is really interesting.
on how many pair and batch did you conduce your experiment ?

Apisto ranch,
geez where do you live ? i cannot believe USPS dont disserve your area
but if not , god you must be far inside the nature, a dream for me , but let me go down to earth
definitively a book to read , even if it contain some mistake most of the time on pics and id i think

 

[Apisto ranch]

I live on the thrid largest cattle ranch in the U.S. the 6666. I'm 55 miles from city and almost 12 miles from my mail box. LOL Yea it's in the middle of nowhere u.s.a.. It's Beautiful but so far from the norm. A lot of people thing I'm a little nuts for wanting to live here. The nearest person to me is 20miles.
I have everything delivered to my Mother-in -laws house and we meet half way to pick it up. I'm ordering the books Cichlid atlas,1,2 and the other one I beleave it's the datz or south american dwarf cichlids. Not to sure of the name. But I'll find it. again. LOL
My kids get up at 5 am to meet the school bus by 6am. They love it here. as do I

 

[blueblue]

Thanks Zapisto:

hmm, for diplo, i bred a pair at different temperature for 4 batches of fry;
for Eliza, there're tens of batchs bred and tried. For the others, i could not remember, but the results all turned out to be more or less consistent with Romer's theory. ^.^

Besides species, i also believe that pH would play a role.

In technical terms, if i focus on one species of apisto, called i, and
i take the chance of getting male in a batch of fry for this species i
as a function F_i_(.), then pH (x) and temperature (y) become two variables. Romer believes that F(x,y) is increasing in y for all i (and for
a reasonable range of y) when x is fixed.

While my experience provides counter examples to his claim,
and i even doubt whether F_i_(x,y) is monotone; and it will be interesting to
see if this function F_i_(x,y) is concave, convex, or monotone in a two-dimensional space x-y.

very interresting reading.

Blueblue ,
you result is really interesting.
on how many pair and batch did you conduce your experiment ?

Apisto ranch,
geez where do you live ? i cannot believe USPS dont disserve your area
but if not , god you must be far inside the nature, a dream for me , but let me go down to earth
definitively a book to read , even if it contain some mistake most of the time on pics and id i think

 

[Mike Wise]

I would have to find one of the 2 scientific papers that Uwe & Wolfgang Beisenherz wrote, but as I recall they studied 37 different apisto species. Temperature was tightly controled, as were other environmental conditions. If I recall correctly most species values were based on 10+ spawns (the lowest was 4). Every effort was made to raise every viable egg to maturity. The detailed work involved was extreme, to say the least. In every case pH had less effect than temperature on sex until extremes occurred (causing major losses of fry). In each case a temperature around 26ºC/79ºF resulted in approximately a 50/50 sex ratio. Higher temperatures in most cases led to more males; lower, more females (the oposite was true for A. caetei). If you are into statistical analyses, the papers provided all of the data use to obtain the results.

 

[blueblue]

Thanks Mike for the information. I just have my concern that,
if one wants to do a kind of truely scientific sensitivity analysis for two variables pH and temperature, say pH from 4.5 to 7.0 (0.2 as each increment), and temperature from 20C-30C (1C as each increment), then we have the following combinations:

For each pH, say pH = 4.5, we have to try temperature at 20, 21, 22, ..., 30;
for pH = 4.7, we have to try temperature at 20, 21, ..., 30 again...
... So, the combination is huge and i am sure that Romer didn't do so.

While to challenge a claim, it is easy by just finding a counter example.

I haven't read the papers, while my understanding is, Romer has assumed that pH doesn't matter much (it could be a fatal scientific error), then he has conducted the experiments under a controlled environment for different temperature. I say that it could be a fatal error because if the male ratio is a function of pH and temperature, one cannot conclude the feature of the function by fixing one variable and studying the other. I believe that what he could conclude, scientifically, is that: under his pre-set pH values and for the species he tried, temperature got that impact he mentioned BUT the results could not be generalized for all species and under any pH value...

I would have to find one of the 2 scientific papers that Uwe & Wolfgang Beisenherz wrote, but as I recall they studied 37 different apisto species. Temperature was tightly controled, as were other environmental conditions. If I recall correctly most species values were based on 10+ spawns (the lowest was 4). Every effort was made to raise every viable egg to maturity. The detailed work involved was extreme, to say the least. In every case pH had less effect than temperature on sex until extremes occurred (causing major losses of fry). In each case a temperature around 26ºC/79ºF resulted in approximately a 50/50 sex ratio. Higher temperatures in most cases led to more males; lower, more females (the oposite was true for A. caetei). If you are into statistical analyses, the papers provided all of the data use to obtain the results.

 

[lab]

Well, we just have to read the articles now, don't we :wink:

I say that it could be a fatal error because if the male ratio is a function of pH and temperature, one cannot conclude the feature of the function by fixing one variable and studying the other.

It is still fair to conclude on the temperature variable though, which by the way is a much more easily controlled variable in our aquariums than is pH. I do not think that Römer and Beisenherz concluded that pH had no effect either. Nor did they necessarily beforehand assume that pH had no effect, I guess they just wanted to investigate one of the variables: temperature.

Other than that I agree that you should be careful in generalizing the conlusions

Best regards,
Lars

 

[Mike Wise]

With most species, Römer bred them at 3 different pH values. In most cases the number of viable eggs (those that hatched) varied with pH, but not the sex ratio of the fry.