Apisto Fry: Temperature and pH
Contents:
- Sex ratios
by Pete Johnson <petej/wordsanddeeds.com> (Wed, 22 Jan 97)
- Uwe Romer's study on sex ratios, temp, & pH
by mengerin/cs.utexas.edu (Wed, 22 Jan 1997)
- RE: male female ratio
by Rusty Witek <jwitek/stetson.edu> (Mon, 14 Jul 1997)
- Romer & Beisenherz's paper on sex determination by temperature
by "Francis Brian O'Carroll" (Frank) <ocarroll/acm.org> (Thu, 23 Jan 1997)
- Fwd: me again (moina info request)
by "Ed Pon" <edpon/hotmail.com> (Mon, 13 Oct 1997)
- Fwd: Re: factors relating to growth
by "Darren J. Hanson" <djhanson/calweb.com> (Tue, 30 Sep 1997)
- Gibbiceps & temperature
by Pete Johnson <petej/wordsanddeeds.com> (Thu, 11 Sep 97)
- Sex Ratio Forecast
by Jota Melgar <jsmelgar/compuserve.com> (Tue, 10 Feb 1998)
- Sex Ratio Forecast
by swaldron/slip.net (Steven J. Waldron) (Tue, 10 Feb 1998)
- Apistogramma borelli
by Mike & Diane Wise <apistowise/bewellnet.com> (Wed, 20 May 1998)
- Romer's Sex Article
by Mike & Diane Wise <apistowise/bewellnet.com> (Thu, 30 Jul 1998)
- Outdoor Apisto
by Mike & Diane Wise <apistowise/bewellnet.com> (Fri, 21 Aug 1998)
- pH & breeding success; was: testing?
by Mike & Diane Wise <apistowise/bewellnet.com> (Fri, 11 Aug 2000)
by Pete Johnson <petej/wordsanddeeds.com>
Date: Wed, 22 Jan 97
To: "Michael F. Jacobs" <Michael_F._Jacobs/cat.pinellas.k12.fl.us>,
>I've read that in fact the sex is determined not at conception but in
>the first 2-3 weeks of the life of the fry...
Uwe Romer and Wolfgang Beisenherz studied the effect of temperature and
pH on 33 species of Apisto fry and found that during the first month of
development low temperatures (below 76 F -- the "cool" test tanks were 74
degrees) produced more females. Low pH (5.5 and below) produced more
males, but had less influence. If you want balanced sex ratios, try to
keep your tanks at 76 degrees during the first month of fry development.
That may be a challenge in Florida. :-)
>Whewwww is anyone up for writing a book???????
Uwe's book is at the publisher's, according to David Soares.
Pete Johnson || Two approaches to the same problem:
San Jose, CA || flying fish and penguins.
by mengerin/cs.utexas.edu
Date: Wed, 22 Jan 1997
To: apisto/aquaria.net
Ok, here's a summarization from Jan, 1997 TFH's Wayne's new World.
Correlation between temp & sex ratio was significant for 33 species.
At 23C ratio was skewed towards females.
At 29C " " " " males
A. caetei was an exception which did not skew relative to temp.
However, pH was a role in A. caetei which did not influence the others
as did temp.
There does seem to be windows for when temp can make a difference.
Broods transfered to the opposite temp had the following results
After 33 days had characteristic of their initial spawning temps.
Up to 3 days had the characteristics of the final temp in transfer
After 3-33 days had a proportional and linear distribution relative
to the time line (so transfer at 15 days produced a nearly 50/50 ratio).
Buy the mag for more details.
Cheers,
Matthew
by Rusty Witek <jwitek/stetson.edu>
Date: Mon, 14 Jul 1997
To: "'apisto/majordomo.pobox.com'" <apisto/majordomo.pobox.com>
For what it's worth, the recently arrived July 1997_Cichlid News_ has an
article on "Cichlids and Science: Sex Determination." I'm no scientist,
but some relevant points:
Romer and Beisenherz (1966) found that low pH *or* high temperatures
favored males in apistogrammas.
Francis and Barlow (1993), in an experiment on C. citrinellum, found that
size itself was meaningful. That is, they raised 74 fry to six months,
then moved the 34 largest to their own tank. You'd think that these would
be mostly males, but at a year each group was roughly 50/50 male-female,
with the largest fish being the males.
FWIW.
Rusty
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by "Francis Brian O'Carroll" (Frank) <ocarroll/acm.org>
Date: Thu, 23 Jan 1997
To: apisto/aquaria.net
Wow, finally an explosion in informed apisto traffic!
The Journal of Fish Biology has a publisher's page at
http://www.hbuk.co.uk/www/ideal/journals/jb.htm
and by clicking on the abstracts link you can eventually locate
the incredibly long http address of
<http://www.idealibrary.com/cgi-bin/www.idealibrary.com_8100/fetch/01010158040402070f010702075006010f000002095c0003060e06015209040654010e080400075307050f550007005b020e0302050051030252540759570707545705070e07/130:1120:1707/15>
I found the following abstract:
Environmental determination of sex in Apistogramma (Cichlidae) and two
other freshwater fishes (Teleostei)
U. Romer, W. Beisenherz
Environmental sex determination by temperature could be revealed
significantly in 33 Apistogramma-species and in Poecilia melanogaster.
In some, but not all, Apistogramma-species pH also influences the sex
ratio, whereas neither temperature nor pH affect the sex ratio of
Pseudocrenilabrus multicolor victoriae. The sex in offspring of A.
trifasciata is determined within a sensitive period of about 30 to at
least 40 days after spawning.
Keywords: Apistogramma, Cichlidae, environmental sex determination, pH,
sex ratio, temperature,
Journal of Fish Biology, v 48, n 4, April, 1996, p714-725 (ID jb960072)
Copyright (C) 1996 The Fisheries Society of the British Isles
Unfortunately, I couldn't figure out whether or not I could order an
copy of the article online. If anyone finds out, please let the list know.
You may be able to search the abstracts for more apisto references at the
site, it is worth looking into for those with time. There's
plenty of info on one's other favorite fish groups there too.
Frank O'Carroll
Tokyo
by "Ed Pon" <edpon/hotmail.com>
Date: Mon, 13 Oct 1997
To: apisto/majordomo.pobox.com
------- Forwarded Message
Date: Fri, 10 Oct 1997 10:06:36 PDT
>BBS it's a good food but maybe giving two different types of food will
>fishes to grow better and faster.
>
>Simone Vicini (psvicini-at-mdnet.it)
>
In the current issue of Tropical Fish Hobbyist magazine, in Wattley's
column on discus, Wattley mentions that growing discus should be raised
in harder water than what is used for breeding because they need some of
the elements for growth (losely paraphased because I don't have the
article with me). This supports some of the earlier postings where a
couple of people felt their baby apistos grew better in slightly harder
water.
Feeding a variety of foods is better because we just don't know exactly
what crucial elements may be missing if we fed only one type of food.
------- End of Forwarded Message
The message above from Ed Pon got bounced accidently
- Frank O'Carroll, Apisto List Admin.
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by "Darren J. Hanson" <djhanson/calweb.com>
Date: Tue, 30 Sep 1997
To: apisto/majordomo.pobox.com
>In addition, I have talked to more than one discus breeder who felt
>their fry grew better in slightly harder water than the water in the
>breeding tank. I have no statistics to prove this, nor have I ever
>attempted to test this.
>
What I do is remove the pair to another tank and let the fry grow out more
until they can be put into a 55 gallon tank. Other times, when space is low,
I leave the fry in their tank and do more water changes more often. (Instead
of 50% once a week to 25% everyday.) At one month of age I start acclimating
my apisto fry to hard water. It makes the sale of the fry easier for the
stores to handle once acclimated and other hobbyists won't need to be in
such a fright that they bought fish that require soft water right now. I'm
sure this chases many people away from apistos for the first time because
they aren't sure they want to invest money into an RO unit for one tank.
When I'm not spawning the adults, they too are acclimated to the harder
water. I housed a beautiful pair of Dicrossus filamentosus for over a year
in harder water until I sold them two months ago at the PCCA meeting.
With the change over to harder water and the addition of other foods I found
the fry to grow more rapidly. I don't know if it just because of the
slightly harder water. I had a 55 a month ago that housed a group of A.
cacatuoides for growout and had been acclimated to the harder water for over
3 months. I was totally shocked when I went to remove all the fish for sale
that they had actually been spawning in the tank!
I don't know if this classifies as a test.
Kaycy
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by Pete Johnson <petej/wordsanddeeds.com>
Date: Thu, 11 Sep 97
To: "apisto" <apisto/majordomo.pobox.com>
On 9/11/97 10:02 AM, Ed Pon edpon-at-hotmail.com wrote:
>This fish seems to be extremely difficult to keep alive just based
>on my experience.
I can keep them alive with no problem -- other than the first group that
Ed & I bought from a local dealer. Those fish died within a few days,
probably from damage suffered during shipment.
A. gibbiceps which have I have subsequently acquired do well in my tanks,
but I have yet to see any sign of spawning and some of them have been
here close to a year.
Uwe Romer recently visisted my fish room and remarked that some of the
tanks were a bit warm for spawning -- he singled out tanks with A. sp.
"Pandurini," A. sp. "Sunset" and A. nijsseni, based on their habitats,
which he said are forest pools. These tanks will cool as our local
temperature drops, but it reminded me of the importance of water
temperature, and that we should note it when talking about spawning.
Ron Coleman, a local researcher, has conducted experiments (I believe
with Midas cichlids) and verified that they have strong temperature
preferences for spawning. He hooked together several tanks with
variations of a couple of degrees apiece and allowed the fish to select
their setting.
Which brings me back to A. gibbiceps. I know that Mike Jacobs, who has
spawned them, lives in Florida. I also know that he has talked about
skewed sex ratios in developing fry (of other Apistos). Both of these
clues suggest to me that his fish room is pretty warm. Does A. gibbiceps
perhaps require a high temperature to spawn?
---------------------------------------------------------
Pete Johnson / San Jose, CA / petej-at-wordsanddeeds.com
---------------------------------------------------------
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by Jota Melgar <jsmelgar/compuserve.com>
Date: Tue, 10 Feb 1998
To: "INTERNET:apisto/majordomo.pobox.com" <apisto/majordomo.pobox.com>
Dionigi wrote:
> Point 1: =
> Say that a scientist like Romer performs a study on the sex ratio of
> Apistos in relationship to pH and temperature.
> He or she will use a given number of pairs to replicate a given number
> of spawns for each specific water condition, from which the average of
> the sex ratio for each will be calculated. Given perfect study
> conditions, this average will be very realistic if it is based on an
> adequately large number of pairs for each pH and temperature condition,=
> because each individual spawn will have a different sex ratio, but all
> together, when averaged, they will provide a good GENERAL description o=
f
> the situation. The mean will in other words summarize the variability o=
f
> the individual spawn observations. =
I do partly agree with you. The key word here is "adequately large number=
s
of pairs for each pH and temperature condition". My main criticism for
Romer's paper is that in several species he did not use enough replicates=
=2E =
I do disagree in that the mean does not summarize variability, only
variance and standard deviation summarize variability. All the mean does =
is
measure central tendency. For example, if you get the mean (average) of s=
ay
10 and 2 you get 6. The same mean you would get for 7 and 5. So, even
though both sets of numbers have the same mean, the first one has the
larger variance.
> Point 2:
> Now, say that a week later Mr. Scientist receives a donation of another=
> large batch of pairs of apistos, he/she has free time, and it is decide=
d
> to duplicate the experiment.
> Well, this time not only as before each individual spawn (replicated in=
> exactly the same condition) will have a sex ratio different from each
> other, but also their mean will not be absolutely identical the one
> previously found. It will be in fact different, on the basis of the
> number of pairs used in this second experiment, and on the basis of the=
> intrinsic variability of the phenomenon being investigated. This is
> due to the fact that there is also a variability in the sample mean.
Given that the second experiment is also done with an adequately large
sample size and having a high level of significance (i.e. <0.001) in the
first experiment, the results Mr. Scientist gets might not be exactly the=
same but, they should fall between the confidence interval of the first
experiment.
> This is way there are indeed statistical procedures that allow the
> scientist to say (instead of "in such conditions you should see such
> and such sex ratio"), "if you duplicate my conditions you have a very
> high probability to observe a sex ratio comprised between ....(low end
> of the ratio) and .... (upper limit of the ratio)", which gives a much
> more realistic presentation of what to expect. Depending on how large
> the original study is, and the natural variability of the event, these
> intervals of probability can be very narrow (say, between 1:1 and 1:1.2=
)
> or very large (say, expect between 5:1 and 1:30). =
Exactly. When we look at the results we should not focus on absolute
numbers alone but on the numbers in association with their significance
level / confidence interval, which is a fancy word for how certain I am o=
f
my results.
> I do not have Romer's paper (is there anyone available to fax or mail i=
t
> to me, if it is in English? E-mail me, thanks), but unless the study wa=
s
> extremely large, it is unlikely that the estimates calculated allow a
> very precise forecast. They may however provide a useful guidance of th=
e
> general rules and trends of the gender ratio determination, which is
> still an extremely important discovery. =
That's the way how I take Romer's paper for most species. Send me your fa=
x
number and I'll send you a copy of it.
Good discussion by the way.
Regards,
Julio Melgar
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by swaldron/slip.net (Steven J. Waldron)
Date: Tue, 10 Feb 1998
To: apisto/majordomo.pobox.com
>I do not have Romer's paper (is there anyone available to fax or mail it
>to me, if it is in English? E-mail me, thanks), but unless the study was
>extremely large, it is unlikely that the estimates calculated allow a
>very precise forecast. They may however provide a useful guidance of the
>general rules and trends of the gender ratio determination, which is
>still an extremely important discovery.
Hi guys,
Good discussion. I have to admit to ignorance of Romer's findings, I'd
appreciate a copy as well.
I'd like to expand the discussion with another consideration, a bit
speculative but grounded in natural selection: We are assuming a 1:1 ratio
is the norm or ideal in Apistos. For most vertebrates, this seems to be the
case when the return from parental investment in offspring either sex is
equal. But there are exceptions, and some of these have shown the adaptive
nature of a flexible sex ratio. Polygynous apistos at least (e.g. A.
cactuoides) might provide one of these exceptions. A parent apisto's
interest in reproducing is to continue its genetic line, grandchildren in
the least. Male offspring have an enhanced ability for continuing the genes
by virtue of their reproductive strategy (multiple mates). Colorful,
territorial males also might suffer increased mortality (more risk of
predation, increased competition for territory, longer distance dispersal
etc.)and decreased reproductive success in non-territorial males than
females. Therefore, a sex ratio weighted towards males at conception seems
highly adaptive. As offspring mature and differential mortality between the
genders set in, the ratio is more equalized and may eventually reach 1:1 or
even female biased.
If we can deduce anything from Romer's data (or at least what I have seen
of it here), it is that different water conditions have variable effects of
offspring sex ratio. This seems a possible adaptive response to changing
ecological conditions and the social structure of the local population
throughout the wet/dry seasons. Imagine this scenario: At the end of the
dry season when water bodies have shrunken, fish are more exposed to
predation, flashy, territorial males have been heavily predated upon, it
may be more adaptive to produce more males to fill this vacancy when the
first rains of the wet arrive. The water chemistry changes at this time may
dictate this sex ratio. You can imagine other scenarios for differing water
conditions during the year. I'm rambling, but in essence if we want to
produce a specific sex ratio in captivity, we need to go into the field and
understand the conditions (water chemistry, demography or otherwise) that
are conducive to that ratio naturally. Captive observations of water
chemistry/sex ratio experiments with too few replicates can only (IMHO)
produce too many speculations.
- Steve Waldron
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by Mike & Diane Wise <apistowise/bewellnet.com>
Date: Wed, 20 May 1998
To: apisto/majordomo.pobox.com
IDMiamiBob wrote:
> Slick. But I'm not sure it's SODIUM bicarbonate. Except I'm sure it isn't
> anything divalent like Ca or Mg, which would show on your basic hardness test.
> Can I test it somehow before I start, or is it just unlikely to be anything
> else? In which case it's worth a try.
>
Are you living in the Miami, FL area? If so your water is perculating through an
old coral reef. The water is leaching CaCO3 (either limestone (calcite) or the
more soluable form aragonite from the substrate. This raises the KH sky high.
> And does carbonate hardness have a negative effect on softwater fish like the
> non-carbonate hardness?
In his book Die Buntbarsche der Neuen Weld - Zwergcichliden, Koslowski states
that, in his opinion, carbonate hardness has more effect on successful hatching of
eggs than does permanent GH. He reported that most of his soft water species
successfully reproduce in 10 - 15º dGH water that had low KH values. But not the
other way around.
Could this be caused by carbonates entering the cell structure of the egg's shell
and hardening it? The carbonates might plug pores in the shells used for
respiration. Since the female breaks open the shells, in most cases, it's not
that the larvae can't hatch out (unless you artificially hatch your eggs). I
don't know, but KH does appear to have more effect on successful hatches than does
GH.
Mike Wise
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by Mike & Diane Wise <apistowise/bewellnet.com>
Date: Thu, 30 Jul 1998
To: apisto/majordomo.pobox.com
My understanding about copyrights (in the U.S. and most western countries) is that
in the strictest sense it it ILLEGAL to reproduce any copyrighted material in any
form, including electronically, without expressed permission of the publisher. On
the other hand, it is an accepted (but not really legal) practice for scientific
papers to be copied for INDIVIDUAL reference purposes. Most scientific journals
are indifferent when it comes to making copies because they don't republish them.
They really don't loose money on these copies. Magazines that are republished,
like Aqua Geõgraphia, and books on the other hand loose money everytime someone
copies them. This is what copyrights protect - loosing money. I imagine copying
one on a web page wouldn't get much notice, but heaven help you if they come after
you! I know of a well known copy store chain that won't photocopy copyrighted
papers. I guess they didn't want any legal problems. Most will copy anything.
Here are the references I posted them earlier, and both are copyrighted.
Römer, Uwe and Wolfgang Beisenherz, 1995, Modifikatiorische Geschlechtsbestimmung
durch Temperatur und pH-Wert bei Buntbarsche der Gattung Apistogramma, in
Symposiumband: Fortpflanzungsbiologie der Aquariumfische, Birgit Schmettkamp
Verlag, Bornheim, p. 261 - 266.
You can still buy this symposium volume from Birgit Schmettkamp (ISBN
3-928819-08-9) for DM 35,- (<$25.00). I can provide an English translation (also
copyrighted - grin) for anyone who can prove they have the original.
The English paper is:
Römer, Uwe and Wolfgang Beisenherz, 1996, Environmental determination of sex in
Apistogramma (Cichlidae) and two other freshwater fishes (Teleostei), Journal of
Fish Biology, v. 48, p. 714-725.
Mike Wise
by Mike & Diane Wise <apistowise/bewellnet.com>
Date: Fri, 21 Aug 1998
To: apisto/majordomo.pobox.com
Ed,
I doubt any will THRIVE, but A. borellii should do well out side since they come
from places with temperatures like those of southern Florida and can handle short
periods of cool temperatures in the low 60ºs F (~18º C). Species coming from the
Llanos areas of Venezuela & Colombia should be able to handle more fluctuations
in temperatures than most. This area is mostly open plains with water holes
(oases) that get very little shade. As such the temperature (air & water) varies
considerably throughout the day. These would be members of the
macmasteri-group. These, however, won't tolerate temperatures much below 70ºF
(21ºC).
Mike Wise
Ed Pon wrote:
> Does anyone have any thoughts on which apistos can thrive while
> living in an environment whether there are significant temperature
> swings between day and night? I asked uwe Romer when he was lecturing
> locally if the water temperature very constant in the wild. Uwe
> indicated that the water temperature does indeed vary a bit between day
> and night in wild--although he did not mention how much.
>
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com
>
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by Mike & Diane Wise <apistowise/bewellnet.com>
Date: Fri, 11 Aug 2000
To: apisto/listbox.com
John,
I'll accept that for the most part lower pH values aid in the success of breeding
apistos. It probably has as much to due with lowering the bacterial count as
stimulating the spawning partners. In the wild sudden lowering of the pH is
probably caused by waters invading the forests during the rainy season and
leaching out tannins from fallen leaves. Whether it is the increased rainfall,
increased breeding habitat, or lowering the pH that stimulates them to breed
isn't really known for sure - maybe a little of each.
Your highly skewed sex ratios may actually be the result of there being a lot of
subdominant "sneaker" males. Try separating the males from the group and see if
more of them pop up. If it is truly skewed toward females to this extent, then it
has more to do with the temperature in the rearing tank than the pH in the
spawning tank. Cool tanks (72-75ºF/23-24ºC) tend to produce considerably more
females. pH has some, but not significant, effects on aggies.
Mike Wise
John Wubbolt wrote:
> Hello All
>
> Ok I've got a question for you all. Does pH really hinder some species
> from spawning or does it trigger them to spawn all the time?
>
> Here's my dilemma. A friend ( Joe Hildreth) came over lately and
> wanted to test my water in some of my aggie tanks, as he was having a
> problem getting his to spawn where as mine spawn like convicts. When
> we did a pH test of a couple of my tanks, we found pH range of 4.5 to
> 5.0. I hadn't realized my water pH was that low in some of my tanks,
> so we tested my tap water pH and found it to be a pH of 6.0 and <1
> degree carbonate hardness and <1 degree general hardness. My question
> is, Is this too soft? And would the low pH hurt my fish. So far from
> general observations, the pH doesnt seem to affect my fish, some really
> seem to love it.
>
> I guess i just was curious if anyone out there has similar experiences
> with water conditions. I think i need to some crushed coral to one of
> my next Cacatuoides grow out tanks, as i have one tank that looks to
> appear like im gonna have over 70 females and not too many males..
>
> John
>
The Krib
Apistogramma/Dwarf Cichlids
The Krib