RobRocksFishTank
Moved On
RobRocksFishTank said:
Male swords can be problematic... sometimes a male won't develop a tail if there's a more dominant male around. That is why some people believe that they can change gender... that's just not what happens with them.
I've seen it happen with a tank full of females. There are even saltwater species that do it. If I remember correctly, some gobies and clown fish are capable of the change. Mother Nature has a way of keeping things going that will baffle the mind.
Byron said:There are reports of swordtails changing their sex, but to the best of my knowledge there is absolutely no scientific evidence of any actual gender change (in swordtails I mean). If anyone has reliable references to the contrary, please post and I will take a look. In some cases this may simply be a slower development, but some adult females have been known to develop male characteristics that might be due to infertility.
As for distinguishing male/female, the only reliable way is the presence of the gonopodium on males. This will be more obvious even before the "sword" extension appears or the males begin to get their colouration.
Byron.
Rather than hi-jacking a thread, I thought I'd continue this in a new one.
I can not provide any good evidence nor do I plan on doing a study to prove that it can happen with swordtails, but I have seen it. Having worked in one of the largest fish departments in the state for many years. I got to see a lot of stuff and hear a lot of stories. I was very aware of the gonopodium and males sometimes not developing swords and females sometimes developing small swords. We had sold the last male of a batch, which happened quite often. I personally checked each female for the presence of a gonopodium but there were nothing but full delta shaped anal fins. A number of days later there was a male in the tank. Can I say with 100% certainty that it wasn't a male? Not really, but I am fairly certain.
I've also seen a feeder goldfish that was frozen in ice for an entire winter start swimming after the ice thawed. I would have said that was impossible but it was a good friends fish and I was over there on a regular basis.