[PfunMo]

Roaming around the local cichlid club site, I found this item. Seems to promote the thinking that all cichlids can change their sex.
http://aquatropicalfish.com/showthread. ... 0d0e6b7d25

While I've done no research into the facts, there are a couple obvious things that say it is not a universal talent among cichlids. We all spend quite a lot of time and energy to get males and females if we want them to breed. Also if they could all just switch sex when they wanted, would an all male tank be possible?

You can read just about anything it seems. Sorting the wheat from the chaff is still a big job.

 

[prov356]

:-? Keeping us in suspense?

 

[PfunMo]

I don't think that's happened before either. Someway I posted a header without the body??? Something funny in computer land tonight.
What I meant to post:

In reading around the local cichlid club, I came across this item. It indicates that they have found that ALL cichlids can change sex at will.
http://www.hillcountrycichlidclub.com/forum/viewtopic.php?f=1&t=8618

http://aquatropicalfish.com/showthread. ... 0d0e6b7d25

Thought you guys that maintain all-male tanks might find some argument with this. Seems to throw the idea of carefully choosing M/F ratios into limbo as well.

Or then we might want to question what we find on the internet?

 

[PfunMo]

Whew! My computer or my brain must be getting fried. I have trouble typing but even I can beat that line of garbage after the second URL . Anybody seen any gremlins headed my way?

 

[zimmy]

The chapter from The Cichlid Fishes referenced in the link you provided actually does not state that ALL cichlids can change sex. In fact the book's author, George Barlow, states quite clearly that this level of sex plasticity only occurs in SOME cichlids. This alone though is pretty amazing.

Like you said, you can't believe everything you read on the internet.

 

[PfunMo]

Thanks , Zimmy. I didn't have the book to check but that sure makes more sense than what the post had in it.

This applies to all species of Cichlids, and can occur at anytime once the fish have hit mating size, they are able to swaitch back and forth between sexes. This use to only be a myth, until a scientist named George W. Barlow studied cichlids and learned that they were able to switch between sexes in his studies.

Most likely going to be one of those stories where something is stated and if it gets enough attention then it becomes"fact" even if the person who did the research states exactly the opposite. Looking through the local club response it didn't seem to meet the level of skepticism I would have expected. I had heard a long time back that some fish were able to change but I found it pretty hard to swallow when they said ALL cichlids could.

Maybe just a bad night for me to be reading forums. Seems I can't trust my typing nor my reading.

 

[prov356]

There's lots of suggestions on the Internet that this may be true, but couldn't find any scientific research on the matter. I did find Barlow's book on Amazon. Use the 'Look Inside' feature and go to page 56. Seems what he's really suggesting is that the cichlids are born with what they need physically to be either gender and environment may determine which gender they become. This has been suggested before though, where temperature and pH, etc can have an influence on m/f ratios. No evidence of freshwater fish changing after reaching maturity as some marine fish are known to do. At least not that I could find.

 

[zimmy]

Not sure if the Look Inside feature allows you to read the whole chapter on sex plasticity but to me one of the points he's making is that although cichlids, like most fish it seems, are more sexually labile than mammals and amphibians, generalizations about their capacity to change sex cannot be made. It's a bit of an oversimplification to suggest that "what he's really suggesting is that the cichlids are born with what they need physically to be either gender and environment may determine which gender they become." Although it seems to be true in some cases (and not any more so than it is for all fish in general) it does not seem so in others.

He also does give at least one example of a cichlid that can change sex after reaching sexual maturity when he describes a colleague having observed a midas cichlid in an aquarium that at one point laid eggs and then at another point fertilized the eggs of another female. He is careful to emphasize that widespread conclusions should not be drawn from this single species.

In the final paragraph of the chapter he states explicitly "some (cichlids) have the capacity to alter their sex from female to male,"(emphasis added) clearly contradicting the views being circulated on the net.

 

[PfunMo]

Seems pretty much rehashing and maybe adding a bit to a pretty old story. I just find it interesting how some small items can get to be really big news as if it was a truly new subject. To me the bottom line would be that if it is a common trait we would see it more often. Simple show-me thinking. When we start having fry in our all male tanks, then will be a good time to believe! Sure will mess with a lot of thinking if it becomes common. Those poor drab females might see quite a bump in price, huh?

 

[Manoah Marton]

Interesting. Actually, in the magazing Tropical Fish Hobbiest, there was a story about a single female JD and pleco in a 55 (never with a male) and one day there were eggs, and then a few days later fry. This was explained because some (or all...can't remember) female cichlids can somehow produce enough sperm to fertilize eggs. It was basically marked off as a miracle.

And Prov356...I just feel the need to recognize, once again, your ability to question whatever is presented. That is such a good skill, and I like it how you yet again look into and research what is provided, and then make a decision (true or false) based on there. Your really one of the people who makes this such an educational forum...not just mindless people always agreeing with eachother. So...everybody give a virtual high-five to Prov356!!!

 

[dwarfpike]

Sadly, my library is still in storage ... so finding the article I am mentioning won't be found anytime soon. Some heavy hitter in the aquarium circles in the early 80's did have a female Crenicara punctulatum that switched to male if I remember right. And we are talking laying eggs successfully to fertilizing eggs successfully. But I can't remember whom owned the fish in question. Tis been years since I read the article, but I suppose someone with more ambition than I on a friday night can look it up.

And while it's not scientific evidence in the truest sense, it is compelling if you choose to believe the report by whomever it was.

 

[PfunMo]

That is the thing that we find the longer we look at things. Never trust information just because it is written. While there are cases where this is reported and there may even be cases where it could be verified, that does not make it true that all cichlids can do this. My main proof would be the number of tanks maintained as male-only for years. If they could switch at will I'm sure there would be far more fry showing up in all-male tanks. That it does not happen every day in the millions of tanks around is proof to me that it could happen but is not likely.

To me it is interesting but should not be presented as true that all cichlids can do it.

 

[Number6]

anyone on the internet loses a good chunk of their credibility when they label things incorrectly...
"Plastic sex" just about made me spew my coffee onto my computer! :lol:

Sexual Plasticity in cichlids is a well studied topic and one can easily see it in apistogramma and the like. Their can be a few abnormal events in any animal (and even in mankind) and then there is the norm for any given species... there is NO norm for all cichlids.

To date, there has been no normal event recorded where a fertile adult cichlid has switched gender and gone on to be fertile. There isn't even much trustworthy anecdotal evidence either... usually just some one off person suggesting that their cichlid changed gender despite much more logical and common explanations.

 

[zimmy]

"Plastic Sex" is actually the title of the chapter addressing the topic under discussion in George Barlow's book on cichlids. That's almost the only thing represented from the book accurately in the link the OP provided.

 

[PfunMo]

Plastic sex? Oh, yeh, I've heard of that but I thought it was mostly for college age guys.

 

[zimmy]

Plastic sex? Oh, yeh, I've heard of that but I thought it was mostly for college age guys.

:lol: