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Mostly male killies? (Read 4014 times)
Jenn
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Mostly male killies?
Mar 3rd, 2019 at 9:13pm
 
I have read in two different places that roughly 90% of newly hatched killies are males. We want a ratio of 1 male to 2 females for a breeding trio. What do we do with the rest of the males or is 90% only applicable for certain strains?

Thanks!
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Andy Jameson
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Re: Mostly male killies?
Reply #1 - Mar 4th, 2019 at 3:14pm
 
It's a complicated question, Jenn.   I don't believe there is any species that consistently throws 90% of one sex (though some have that tendency).    Certainly no ratio like that exists for killies generally.

Yes, some species tend to have batches of fry turn out exclusively one sex, though not always the same sex each time.   SOME of this has been shown to have a cause.  I believe A. gardneri has been shown to produce more of one sex at low temps and the other at high, though I can't remember which is which.  pH and age of the parents has been shown to influence ratios in some fishes, but I don't know about those in killies specifically.

One thing which absolutely tends to favor males over females after the eggs hatch is lack of proper food when small.  Testosterone being a growth hormone, the males grow faster so, if food is scarce, they will get a little bigger and then get more of the food because they are bigger.  Soon the small (mostly female ones) get none.   I have seen this in my own experience.

Once in a while though, you just get one batch of 16 juvies and they all turn out to be female.  Too unlikely for chance, but you never really figure out what was different about that batch from the one before or after which were about equal.

Andy
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Jenn
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Re: Mostly male killies?
Reply #2 - Mar 4th, 2019 at 4:48pm
 
Thank you for your response, that is both helpful and encouraging!
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James Langan
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Re: Mostly male killies?
Reply #3 - Mar 4th, 2019 at 5:59pm
 
Jenn,

What species specifically.  This really makes a difference how one approaches this problem.

Let us know,  Jim Langan
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Jenn
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Re: Mostly male killies?
Reply #4 - Mar 5th, 2019 at 7:30am
 
Right now I have Fundulopanchax Gardnerii that I picked up at a LFS. I had a male and two females for nearly two months but both females managed to escape through an opening less than 1/4" wide (I thought the first got out, unnoticed, during a water change until the second escaped later that week). I was devastated because I underestimated their abilities and essentially killed them (but have since closed every possible opening at the top). I had just made 2 yarn mops to start trying to breed them. I noticed a fry in at the top of the tank the next week and another fry two weeks later so it is possible any females might have died right away since I wasn't feeding any small foods at the time. Both are old enough to be sexed now and both are males, so I am left looking for 6 females!!

I'm wondering if it wouldn't be better to keep these three as bachelors and start trying to breed fresh with a different 'easy' species instead.
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Andy Jameson
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Re: Mostly male killies?
Reply #5 - Mar 5th, 2019 at 1:45pm
 
You might restart with a different species since getting a pair probably won't be any more trouble than just a female.  but I don't think you will find a species much easier than gardneri.  I mean, you already did it without even trying!

There is a good discussion of this topic in an older post:

http://aka.org/cgi-bin/yabb2/YaBB.pl?num=1491629116/7
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James Langan
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Re: Mostly male killies?
Reply #6 - Mar 6th, 2019 at 6:39pm
 
Jenn,

Try posting a photo of your males.  Your photo doesn't need to be a great one.  You might try contacting the LFS to determine the actual species.  Unfortunately gardneri is a sub-genus and there are several possible species.

A photo would help immensely,  I hope this helps,

Jim Langan
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Jenn
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Re: Mostly male killies?
Reply #7 - Mar 6th, 2019 at 7:37pm
 
I took some photos of my fry at home and added a couple photos of my trio from early January.

https://photos.app.goo.gl/PUQ8xkLqFU6aYrW79

I'm not a photographer, and the fry seemed to know I wanted a picture of them, because they would pass slowly by my camera then dart away as soon as I tried to snap the photo.
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Jenn
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Re: Mostly male killies?
Reply #8 - Mar 6th, 2019 at 7:55pm
 
Andy, thanks for the link. That is exactly the information I am looking for. It looks like Jim weighed in with the answer on that one.

The lfs only had them labeled as gardneri Sad

My photos aren't that great, but the Gardneri I have look exactly like the nigerianus makurdi except mine have a white edge on the lower fins. I'll have to look through photos and try to figure out which species I have.
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James Langan
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Re: Mostly male killies?
Reply #9 - Mar 6th, 2019 at 8:26pm
 
It would be useful to see a photo of the fish if possible, even if not that great of a photo.
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James Langan
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Re: Mostly male killies?
Reply #10 - Mar 6th, 2019 at 8:54pm
 
Jenn,

I'm going to be in KCK later this month and several times during April.  I could bring you pairs of Fp gardneri Innedere and FP gardneri N'Sukka.  I'll email you some photo links from the AKA KMI killifish Gallery.  I hope this helps,  Jim Langan
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Jenn
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Re: Mostly male killies?
Reply #11 - Mar 6th, 2019 at 8:54pm
 
Jim, that would be great. I live very close to KCK.

Let me know when you are in town and what I will owe you!
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« Last Edit: Mar 6th, 2019 at 10:19pm by N/A »  
 
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Jenn
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Re: Mostly male killies?
Reply #12 - Mar 6th, 2019 at 10:05pm
 
Trio:
https://i.imgur.com/oC3ZAYC.jpg1

Juvenile:
https://i.imgur.com/JVOziAJ.jpg1

Sorry, I have been messing with this for a while and for some reason, even though I am using the img tag, all I get are links.
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Jenn
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Re: Mostly male killies?
Reply #13 - Mar 7th, 2019 at 6:29pm
 
I found the KMI photo gallery. Both the Innedere and N'Sukka are beautiful. I especially like the bright orange on the Innedere.

Clicking around in the photo gallery I think mine adult is a Gradneri Udi based on the white edge on the bottom of the tail fin.
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