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Sailfin Mollies

Started by Guest_teleost_* , Nov 08 2006 09:21 AM

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37 replies to this topic

#21 Guest_scottefontay_*

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Posted 08 March 2008 - 10:44 PM

another quick follow-up...at what age is the sex decided? If I want to ensure both males and females in 4 albino young when should I seperate them or is sex predetermined? I know that sword tail females can switch-hit when the team needs another player are mollys the same way?

#22 Guest_mikez_*

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Posted 09 March 2008 - 07:38 AM

another quick follow-up...at what age is the sex decided? If I want to ensure both males and females in 4 albino young when should I seperate them or is sex predetermined? I know that sword tail females can switch-hit when the team needs another player are mollys the same way?

I'm finding that sex, at least male sex, is a function of the population and what dominent males already exist.
See my post about the situation as it unfolded in my colony which started with, I thought, a trio [1:2].
http://forum.nanfa.o...?showtopic=3601
As a follow up on that post, the last wild male, the one shown in the pics, has died, apparently from old age. Within a week of him dying, half a dozen female looking mollies all sprouted gonopodium including some only about 2 inches long. All seem to be functional, at least they can articulate, and all are courting. Only the biggest has started coloring up and his dorsal is starting to grow. As of yet, I have not witnessed any aggression between the "new" males.
FWIW, my understanding of the situation with the Poecilia is that the females don't actually "switch hit", but are genetic males that have repressed male features apparently to allow them to coexist with dominent males without aggression. Some environmental trigger, like the death of the dominent male, causes them to "turn into" males. I do not believe actual females capable of giving birth can turn into functional males, able to sire births.
This IS possible with some marine fish, but best understanding of the literature is that it is not possible with the live bearers.
Any of you educated guys feel free to jump in and help me out here...

#23 Guest_fundulus_*

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Posted 09 March 2008 - 11:14 AM

There's no record of sequential hermaphroditism in poeciliids. But I think there's some observations of elderly female Xiphophorus developing a gonopodium without functional testes. Mike's observation on some male mollies becoming "more male" in response to social restructuring is exactly right. There's some process whereby previously low ranking males can perceive that there's a chance they could succeed as higher ranking males, so a sudden surge of various testosterones and hormones such as AVT trigger a physical response to develop a gonopodium and other more obvious male attributes. In a small tank, "there can be only one" might describe the situation for alpha males.

#24 Guest_scottefontay_*

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Posted 09 March 2008 - 09:21 PM

I have had swordtails that looked like females, even got fat and thin over and over again, like they had young (they were in with 4 rope fish so no young ever confirmed...) that "became" male with sword and all. Very aggressive also.

This is the male and definate female sailfins I just got...

second pic had the flash on by accidient, but the only one I could get with his sail up...sorry I'm not great with the camera.

Attached Images

#25 Guest_mikez_*

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Posted 09 March 2008 - 10:05 PM

Those are nice looking. They look like they are not far off genetically from the wild ones I got. Mine have a bit of that nice orange color to them. I could see selective breeding producing that color.

#26 Guest_scottefontay_*

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Posted 10 March 2008 - 05:41 PM

Those are nice looking. They look like they are not far off genetically from the wild ones I got. Mine have a bit of that nice orange color to them. I could see selective breeding producing that color.

there are 5 albino young too.

#27 Guest_mikez_*

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Posted 10 March 2008 - 05:55 PM

I'll be interested to hear how they do. It might be in both of our interest to make a swap. I'd love new blood for my colony and color is always good. You could use some of those robust pure wild genes.

I'm not refering to the albinos BTW. I'm not a fan of albino. I do like the orange though.

#28 Guest_scottefontay_*

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Posted 14 March 2008 - 08:50 AM

I'll be interested to hear how they do. It might be in both of our interest to make a swap. I'd love new blood for my colony and color is always good. You could use some of those robust pure wild genes.
I'm not refering to the albinos BTW. I'm not a fan of albino. I do like the orange though.

i'm generally not a fan of albinos either, but I appreciate the occurance

#29 Guest_rainbowchrome_*

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Posted 16 March 2008 - 08:27 PM

Sailfin mollies definately manipulate the number of dominant males in a population.Ideal situations bring on larger and more numerous dominant males,whild poor condintions reduce the number.I have seen sailfin populations in marginal environments with almost no male color developing at all,just the gonopodium developes.Salinity and other environmental factors seem th make quite a large change in how males look.

#30 Guest_scottefontay_*

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Posted 17 March 2008 - 03:27 PM

Sailfin mollies definately manipulate the number of dominant males in a population.Ideal situations bring on larger and more numerous dominant males,whild poor condintions reduce the number.I have seen sailfin populations in marginal environments with almost no male color developing at all,just the gonopodium developes.Salinity and other environmental factors seem th make quite a large change in how males look.

that makes sense...when money is tight I forgo flashy clothes too. It would seem that putting energy into developing "extra" finnage only to increase aggressiveness and wasted energy in a stressed population would be counter-productive

#31 Guest_mikez_*

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Posted 17 March 2008 - 09:37 PM

Sailfin mollies definately manipulate the number of dominant males in a population.Ideal situations bring on larger and more numerous dominant males,whild poor condintions reduce the number.I have seen sailfin populations in marginal environments with almost no male color developing at all,just the gonopodium developes.Salinity and other environmental factors seem th make quite a large change in how males look.

I'd be interested to see you elaborate, especially on the salinity issue.
My mollies were taken from pretty much full saltwater. They were back in the mangroves but very close to the Gulf. Most associated species were saltwater or brackish.
I keep them in full fresh, mainly because they inhabit my big planted tank.
So far, none of my second or third generation captive bred males have grown a full "sail". A couple of the biggest are getting good color and the dorsal is growing. I've been assuming sooner or later they would sport full blown sailfins.
Do you think they will not develop the big dorsals?

#32 Guest_NKJohnson_*

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Posted 05 April 2008 - 08:55 PM

Tonight I visited a drainage creek that eventually empties into the San Marcos River (TX) less than 1/4 mile away. Below a small bridge is a pothole about 12x20 feet that for several years I have noticed never seems to dry up. Tonight I went down to try and scoop some gambusia to place in the cattle watering tanks on my place to control mosquitoe larvae this summer. I got the gambusia and a few nice green sunfish but the surprise was the sailfin mollies. I knew they existed in the area but have never netted any wild mollies up except along the coast. They came out of that pothole over a dozen to each dip of the net. I kept a couple dozen including some nice males that are in a small tank next to the computer as I type.

Someone posted that these fish like an algae filled tank and also that they seemed to thrive in a fiberglass tub out back of somewhere. These fish came out of some fairly poor quality stormwater runoff. I placed some in the galvanized water tanks with the gambusia. I have always had a problem with crayfish in the galvanized tanks, copper or something I think. Does anyone know how these fish fair in large galvanized water troughs that are receiving groundwater, actually I guess it's the same groundwater the San Marcos River is receiving, so I guess hard water from a karst aquifer is suitable for these fish.

I'd like to see them flourish in the troughs, is algae growth and mosquitoe larvae sufficient or does anyone think I should throw some other food stuff in for these mollies?

How does one post a photo to this site? (idiot instructions please) In case anyone is interested in seeing these guys.

#33 Michael Wolfe

Board of Directors

North Georgia, Oconee River Drainage

Posted 05 April 2008 - 09:06 PM

How does one post a photo to this site? (idiot instructions please) In case anyone is interested in seeing these guys.

We always want to see pictures... it's pretty easy, if you reply to this message, you will see a green UPLOAD button on the bottom right of the screen. Click the Browse button... find you file... click up load... once it's uploaded click the Manage Current Attachments trianch just above the UPLOAD button and you will be able to add the pics right to the body of your message.

Either write something worth reading or do something worth writing. - Benjamin Franklin

#34 Guest_NKJohnson_*

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Posted 05 April 2008 - 09:55 PM

Thanks Michael. I am going to try the upload of a not very good molly photo but I am waiting for 625 images to import from my digital camera, I haven't cleared it in awhile so this is a good thing, I will put the thing up as soon as I have them on my computer.

#35 Guest_NKJohnson_*

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Posted 05 April 2008 - 10:29 PM

Thanks Michael. I am going to try the upload of a not very good molly photo but I am waiting for 625 images to import from my digital camera, I haven't cleared it in awhile so this is a good thing, I will put the thing up as soon as I have them on my computer.

one of the males

Attached Images

#36 Guest_Skipjack_*

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Posted 05 April 2008 - 11:49 PM

This is interesting, and is answering some questions I have had. I have never researched this fish, but have five I think. Two males rest female. One male is well developed sexually, the other looks like a female with a gonopodium. The sissy male seems way more into reproduction than the masculine one. He is always sneaking in trying to get some love.

#37 Guest_mikez_*

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Posted 06 April 2008 - 07:30 AM

I'd like to see them flourish in the troughs, is algae growth and mosquitoe larvae sufficient or does anyone think I should throw some other food stuff in for these mollies?

Algae growth and mosquitoe larvae are indeed sufficient to support a healthy colony of mollies. Hard, warm water completes the picture. You should have good success with them.

The sex lives of these fish is amazing as this thread implies.
In my colony, the last of the wild males has died and immeditately a whole sh!tload of girlie fish have sprouted gonopodiums. I'm actually concerned that I suddenly have too many males! Only one has colored up and grown a sail, but all of them are sexually active, even some itty bitty 2 inch fish I never would have guessed were mature. Amazingly, they all seem to get along with very little aggression. When the colony was just starting out, the males were relentless at driving off rivals.
There has got to be some connection to sex ratio and conditions in the colony. For some reason my tank has changed from a one male only tank to a bachelor's free for all. I feel sorry for the poor females in there now. I would have to asssume that the population is maxed out and further reproduction would be a strain on the resources of the habitat. There's still lots of babies yet to grow up. From my point of view lots of males makes for a more active and colorful display. It's amazing to me that all these males get along now. It'll be interesting to see how things progress.

#38 Guest_NKJohnson_*

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Posted 06 April 2008 - 09:18 AM

Interesting to know about the males and their aggression. Last night it was just getting dark and I was in a hurry but selected 2 nice males and what I thought were three females for an aquarium in the house. As I was sitting here typing last night I noticed a little agressive behavior by the two big males, by the time I was done downloading and uploading photos I look back over and one small female is belly up....a female with gonopodium on closer examination

Since I had a photo already I took the lot out to one of the troughs and dumped them in, it'll give them more space and hopefully end the violence

Good luck with the tankful of newmales, maybe since it isn't a new space to them
there will not be a territory battle