Help us serve you better. Take a five minute survey. Click here!

jay


 


Archived message board.


Swordtail Sex-Change ?!?!?!?!?!

Badmans Tropical Fish Message Center: General message area: Swordtail Sex-Change ?!?!?!?!?!
  

Sierra

Tuesday, January 22, 2002 - 01:17 am
I have heard form several sources that female Swordtails can turn into males (I think this is supposed to happen when there aren't enough males around). I'm not entirely sure how true this is but when I was in the LFS today I saw three female green swordtails - I would have bought them but when I looked closely at one of them her anal fin wasn't the normal 'fan' shape, it seemed to be a bit elongated and narrowed when compared to the other females (but it didn't quite look like a males gonopodium either). And then I looked at her tail and it seemed to have a small split in the bottom of it as though a 'sword' was going to start growing form it! I know it wasn't just a juvenille male because it was the size of a fully grown female. I wish you guys could see it. It doesn't seem to be a male or a female - something in between! Can anyone shed some light on this, please?

  

joycedonley

Tuesday, January 22, 2002 - 07:24 am
I don't really remember if swords are sexually diamorphic, but I think some African Cichlid are. I'll have to find where I read that as I think sometimes it's a little controversial and just a miss on determining the correct sex in the first place.

  

That_Canadian_Guy

Tuesday, January 22, 2002 - 12:48 pm
Sierra, what happened is the that female is very old. Old female swordtails will develop a gonpodium. Luckily they cannot breed though they will try. They also develop a small sword.

  

Sierra

Tuesday, January 22, 2002 - 04:59 pm
Old? How old? Will she soon be going to 'the big aquarium in the sky'? I didn't want a male but I don't really want an old fish either. But I might just get her anyway because she looked so nice and I'll get her two friends as well She needs a nice place to spend the rest of her days and someone who doesn't mind that she's a 'shemale'!

Hey Joyce, I reckon sexual diamorphism must a 'survival of the species' technique, right? Can males turn into females?

  

joycedonley

Wednesday, January 23, 2002 - 07:08 am
I'll try and look around for the article when I get some time. It was either in one of my books or A fish and I don't think it works the other way around. By the way most livebearers don't live all that long anyways. Not sure on the swords, but I know I read guppy only live 1-2 years. I think it's probably because they are so prolific and also livebearing fish.

  

joycedonley

Wednesday, January 23, 2002 - 08:06 am
Found a marine site with the answer to your question. Most commonly it's female to male ie some wrasse, but the clownfish can go from male to female. I think these sex changes may be more commonly found in marine fish as I also got a hit on tuna!

  

That_Canadian_Guy

Wednesday, January 23, 2002 - 04:05 pm
She won't be going to the 'Aquarium in the sky'for a couple of years in optimum conditions. She can't mat though.

  

Sierra

Wednesday, January 23, 2002 - 05:09 pm
I'll get her and her friends today! I hope they're still at the LFS though.

  

Pandora

Wednesday, January 23, 2002 - 09:57 pm
Hey, let me clear up some confusion here. Swordtails do NOT change sex. There are hermaphrodite fish (joyce, I think you meant this, that they have both male and female genitalia? sexual dimorphism just means f & m's look different, which swordtails are)... and there are fish with potential to really change internal sex organs given environmental stimulus.

HOWEVER, this swordtail issue is different. This was confusing to breeders in the early 70's, but I think the consensus nowadays is largely that they don't actually change sex... they were merely males all along internally, but "late bloomers" (you'll notice that all fry have female-looking anal fins instead of gonopodium when they are born). Not all swordtails mature at the same rate, and some will develope their actual swords even later, sometimes as late as a year old!

  

Pandora

Wednesday, January 23, 2002 - 09:59 pm
I reread my msg and found it a bit confusing itself... just to clarify, when I said there ARE hermaphrodite, I meant species other than the swordtail... usually rare marine species.

  

joycedonley

Thursday, January 24, 2002 - 07:06 am
Pandora I also read that with swords it was mistaken identity due to the development of a gonpodium.I have read though of a few fish that are sexually dimorphic and as I noted most of these are marine fish and it isn't very common just a few species. The marine site only listed wrasse and clownfish.

  

joycedonley

Thursday, January 24, 2002 - 07:08 am
Pandora you can clarify the terms though I got my hit on the changing sex when I did the search on sexual dimorphism?

  

joycedonley

Thursday, January 24, 2002 - 07:14 am
"Much like their amazing ability for changing colors, the parrot fish presents a very inter-changeable mating pattern. In many species the female will become a male during the mating season. Males that are born into the species remain male and tend to surround themselves with many females once they have established a nesting site or territory" Here is another one that will change sex(whatever it's called).

  

joycedonley

Thursday, January 24, 2002 - 07:37 am
http://www.bio.davidson.edu/Courses/anphys/1999/Rice/Rice.htm

Interesting site about many marine reef fish changing sex. Thought you might be interested Pandora if you are starting salt water tanks.

  

Pandora

Thursday, January 24, 2002 - 11:36 am
Here's a few definitions for you guys (probably look in Webster's for the official one, these are off the top of my head and might not be complete):

Hermaphrodite--An organism that possesses both male and female genitalia within the same body

Sexual Dimorphism--Consistent differences between the male and female genders of the same species beyond just basic anatomical genital differences (Examples of animals showing strong sexual dimorphism: peacocks, guppies, swordtails because of the sword... on the other hand, fish that are hard to sex, such as many tetras, show little sexual dimorphism. It is a continuum, and some would argue humans fall in the middle of this spectrum).

Protogyny--An organism that starts out female and turns into a male

Protandry--Other way around

I did a little bit of reading on this after the post, joyce, and I had underestimated how many fish really do change their sex throughout their life! I think actually it's the majority of reef fish that do change sex, rather than the minority, which is very interesting. I think it has to do with the difficulty of finding a mate in a reef ecosystem where territories are pretty small for individual fish, and many don't school in the shallower regions. Just FYI, this is really interesting, but I've also read articles about Pacific Salmon changing sex due to environmental stimuli like seasonal rainfall and pollution!

Anyway, interesting stuff... really makes you think about how our rigid definitions of male and female for humans are not universal in the animal world. There are interesting stories of a desert lizard species which are all female and usually gives birth to clones... they only breed sexually with males of other species. There are also hermaphrodite animals and plants that can fertilize themselves. Or how about this... I used to work in an entomology lab with aphids... they can choose to either breed sexually, or reproduce asexually, giving birth to clones, called parthenogenesis. The interesting part is, a big female aphid can give birth to young that are already pregnant... in effect giving birth to both her children and grandchildren at the same time!

Well, just some random trivia I found really neat...

Ain't Nature wild? =)

  

joycedonley

Thursday, January 24, 2002 - 07:16 pm
I wonder how many reef fish change sex in the aquarium? I wonder if successive generations loose this capablity? I'm not sure a lot of the reef fish can even be tank bred. Guess I'll have to keep reading the saltwater articles in A fish magazine. Those lizards sound really bizarre! Anyways thanks much for the term updates it helped get things straight!

  

Pandora

Saturday, January 26, 2002 - 10:23 am
Sure thing, joyce. I don't know about whether the reef fish would ever change sex in captivity, it would be interesting to research it! To my knowledge, the ones I hear of are all close to impossible to breed, actually close to impossible to sex, in captivity (one of the reasons they are so expensive and there's such a controversy in the hobby about the destruction of the natural reef by this hobby). They probably need really exacting requirements that we aren't able to provide in an aquarium setting, although of course I'm new to reef tanks just like you.

Hey, and I got my first fish for that tank too, joyce... my first SW fish... a yellow tang! He's doing great so far, swimming around and picking stuff off the Fiji live rock. I also bought this guy's half-dead open brain coral, and I feel like I got ripped off already (he was selling everything for a bit much for a tank that was falling apart, IMO, and I wanted to get something just to get out of there and not have come for nothing. The brain coral is showing it's skeleton on one side, but the live side still has color, do you think I will be able to nurse it back to health if I have good lights?

  

joycedonley

Saturday, January 26, 2002 - 12:36 pm
I know from others comments that lights are really important for coral growth.I guess if you do have some color and part of it is living it's certainly worth a try. That marine stuff costs so much in the first place I think whatever you can save is great! BTW those tangs are just gorgeous. I've seen them many times in a couple of Marine shops around here. What did you use for substrate? Do you have any of those shrimp?

  

Sierra

Sunday, January 27, 2002 - 01:34 am
Hi! I got the swordtails, including the 'shemale'. The fish is just like I explained earlier and I don't think I have made a mistake. The fish is as large as the other females (perhaps slightly larger). Male swords are usually smaller the female swords, aren't they? Tha bottom part of the caudal fin is thickened and extenteds aqbout 1/8 in. beyond the rest of the tail. The 'gonopodium' isn't quite right because it is not carried close to the body - it just hangs there and there's still a bit of female 'fan-shaped' anal fin with it. So if its not a sex-changer then I don't know what it is. Maybe it was born somewhere in between? I don't mind though because its a bueatiful fish

  

Pandora

Sunday, January 27, 2002 - 10:15 am
Sierra, as I explained swordtails are not true "sex-changers", but what you're seeing is not uncommon either. A lot of breeders have noted this before. There was a lot of debate in the 70's about it, but mostly it's resolved now... it's a "he" and he's probably just a late bloomer. Give him some time and he still has a chance at developing into a "proper-looking" male.

  

Sierra

Tuesday, January 29, 2002 - 02:44 am
Oh. I didn't really want a male swordtail. But I've got him now so I can't do anything about it. 'He' is more aggressive tham the other two swords, which are definately females. I got a blue gourami today and the 'male' sword was giving it a bit of a hard time. He just kept following it and nibbling its tail. So I trapped him in a clear plastic take-away food container and weighted it down so that it sits on a rock in the middle of the aquarium. He can still see the other fish and they can see him - hopefully this will be enough to cool him off and give the gourami a chance to settle in and become more confident. It's weird because I expected that if anyone would harrass the gourami it would be my krib who chases everyone else away from her caves, but she lets the gourami go inside the caves and explore! Fish personalities are very interesting!

  

Pandora

Saturday, February 02, 2002 - 09:44 am
Yeah, they are interesting, aren't they =) Some fish species are naturally aggressive, but then I've found variation between individuals within the same species as well... bettas and angelfish are a prime example of this.

Just a note on "trapping him" under a clear bowl, however... this is late telling you now, but I hope you removed the bowl and didn't keep him there for long. That does not provide much water circulation if you pinned it close to the gravel, and he could suffocate because of poor gas exchange (it obviously won't be airtight because it's open on the bottom, but the water won't flow well through the gravel). I suggest that you buy a fish divider next time if you have this problem again.

  

Sierra

Monday, February 04, 2002 - 02:59 am
Don't worry, I only kept him in there over night and when I let him out the next morning he was still causing trouble so he has been exiled to the 10 gallon tank with my zebra danios. I will put him back in the main tank when I have cured an ICH outbreak in it He was probably lucky I moved him out, otherwise he would have gotten it too. Also, I had the the 'takeaway' container up the right way with the lid on and before I put him in it I punched a whole lot of holes in it for water circulation. The container was sitting on a rock near the filter outflow so I figured he would be OK for a short while. I now have a 'net breeder' and one of those plastic convertable breeding traps so if I have any more trouble-makers in the future I will put them in one of those. Thanx for your help.

  

Pandora

Tuesday, February 05, 2002 - 12:41 am
Oh that's good. How's the battle going now? You know, your ich problem may not be totally unrelated... when fish are stressed, they are more susceptible to such things, and the bullying can take it's toll after a while. I hope you figure out some way out of both the disease and the incompatibility issues!

  

Sierra

Tuesday, February 05, 2002 - 09:14 pm
Well, I've only been treating for two days and the cysts are already gone (but don't worry, I won't stop treating for at least a week). The fish are a lot happier and their fins aren't clamped anymore. They've also stopped hiding in the rock caves as well. They're still eating and I've been giving them little bits of food 2-3 times a day. I know some people say its not good to feed fish while they're sick. But I think that if the fish are hungry then its a good sign and there's no need to deprive them of food if they want it.

I think it was a combination of things that brought on the ich outbreak:
* The bullying from the male sword (mostly directed at the gourami and the other female swords) and then from the gourami (directed towards everyone) after I removed the sword *sigh and roll of the eyes* My krib can give the other fish a hard time (even though she's the smallest fish in the tank) but I think she's just territorial and doesn't want the other fish in 'her' caves.
* I dropped the temp. in the tank by about 4-5*F over several days to try and reduce aggression (sort of worked). But this may have made the fish more susceptable to disease (esp. the new mollies).
*I introduced a new fish (unquarantined)from a bad petshop the week before.
* I got the mollies the day before I realised the fish had ich. So these new additions (and their bossy behaviour) might have stessed the fish some more.

Plus I think maybe it was 'my time' to have something go wrong. I only started to keep fish four months ago but I have had to major problems (apart from my first fighter jumping out of his bowl - he's fine now) and no deaths

 

Navigation panel.