Vieja Argentea Gender?

  • Phantom
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Phantom created the topic: Vieja Argentea Gender?

Hey everybody. Been a while. I had a minor disaster after mixing a larger wild caught green severum with my juvenile oscar. Ended up with a dead oscar and rehomed severum so stepped back for a while and let my striped Raph have the tank to himself for a couple months. Although I still love oscars my lfs seems to be unable to order any good quality ones (they look terrible). They did however get a group of pricey Vieja Argenteas in. They looked really nice and I chose the largest of the group, hopefully a male, pretty friendly too. I vented him/her but I'm still unsure, the vent looks v -shaped and pointy to me but this fish is still tiny at 3 inches. So it might be too small. Here are some pics...


I've had this little guy for a month now. I think he's grown 1/2-2/3 of an inch. Argenteas from what I've researched are the slowest growing Viejas but get pretty big.
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Darth Nandopsis replied the topic: Vieja Argentea Gender?

Shoot me a video of this guy after he has settled in......I'm usually pretty good @ this stuff. B)

THOSE WHO REFUSE KNOWLEDGE ARE DOOMED TO FAIL.

WATER CHANGES ARE THE LIFEBLOOD OF THIS HOBBY. IF YOU DON'T BELIEVE SO OR SIMPLY DON'T FEEL LIKE DOING THEM, RE-HOME YOUR FISH, SELL YOUR AQUARIUM & FIND ANOTHER HOBBY, AS YOU WILL FAIL UTTERLY, COMPLETELY, & MISERABLY.
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Phantom replied the topic: Vieja Argentea Gender?

I'll have to wait a day or two. After netting him he's suspicious of me again lol.
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Rocksor replied the topic: Vieja Argentea Gender?

If it's either oo or o> then it is a male.
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Darth Nandopsis replied the topic: Vieja Argentea Gender?

Yup, most fish don't take kindly to that.......if this fish was the largest one in a tank full of the same spawn, chances are it's a male. Whenever you can shoot a pic or even better, take a video.

THOSE WHO REFUSE KNOWLEDGE ARE DOOMED TO FAIL.

WATER CHANGES ARE THE LIFEBLOOD OF THIS HOBBY. IF YOU DON'T BELIEVE SO OR SIMPLY DON'T FEEL LIKE DOING THEM, RE-HOME YOUR FISH, SELL YOUR AQUARIUM & FIND ANOTHER HOBBY, AS YOU WILL FAIL UTTERLY, COMPLETELY, & MISERABLY.
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Rocksor replied the topic: Vieja Argentea Gender?

Hopefully, Argentea are not like Amphilophus Citrinellus and can change sex based on population in the environment. There was a study done with something like 40+ Midas cichlids. The largest ones where separated after 6 months. The theory was that the largest ones would be all male. After about another 6 months, they were all dissected. What they found were that in the larger half of the population that 50% were male and 50% were female. They then dissected the other 20+ smallest ones, and found a ratio of 50/50 males to females. Their conclusion was that their original hypothesis was incorrect, and something like sex on certain species of fish are not pre-determined at birth or other factors, and can be based on population need.

I can't remember where I found it, but I know that Jason read the same study, which is why he had 2 Rio Mag Umbees in the beginning. Both turned out to be male. He wanted to make sure that he definitely got a male.

www.ncbi.nlm.nih.gov/pubmed/21740508

Some fishes mature and function as one sex and later transform to the other sex in response to social interactions. Previous evidence suggested that a change in developmental timing may be involved in the evolution of adult sex change in fishes. The most recent support for this idea came from reports that sex in the Midas cichlid, Amphilophus citrinellus, was determined by social conditions experienced at the juvenile stage.

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Darth Nandopsis replied the topic: Vieja Argentea Gender?

I knew live-bearers did that, but not cichlids......but I do have a very good success rate sexing cichlids, with the exception of Oscars & Discus, I don't even try, until they're almost adult size, when there is no doubt. B)

THOSE WHO REFUSE KNOWLEDGE ARE DOOMED TO FAIL.

WATER CHANGES ARE THE LIFEBLOOD OF THIS HOBBY. IF YOU DON'T BELIEVE SO OR SIMPLY DON'T FEEL LIKE DOING THEM, RE-HOME YOUR FISH, SELL YOUR AQUARIUM & FIND ANOTHER HOBBY, AS YOU WILL FAIL UTTERLY, COMPLETELY, & MISERABLY.
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Rocksor replied the topic: Vieja Argentea Gender?

Yeah the study says that is occurs within the first year. After that, the sex is locked permanently set.
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Rocksor replied the topic: Vieja Argentea Gender?

This is the study that I read. In both separated groups, the larger fish were determined to be male.

Social control of primary sex differentiation in the Midas cichlid
RICHARD C. FRANCIS* AND GEORGE W. BARLOW

(1993)
www.pnas.org/content/90/22/10673.full.pdf

Sex in the Midas cichlid, therefore, is determined by relative size in juveniles sometime after they reach 6 months of age or a median size of 52 mm.


Here's another,more recent study that says something different. I've only skimmed it, so I will have to to read it more thoroughly.

deepblue.lib.umich.edu/bitstream/handle/2027.42/55671/roldfiel_1.pdf?sequence=2

EFFECTS OF BEHAVIORAL INTERACTION ON SEX DETERMINATION IN
THE MIDAS CICHLID
Ronald G. Oldfield (2007)
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Phantom replied the topic: Vieja Argentea Gender?

I should have taken more pics but was worried about stressing him too much and did this in about 5 seconds before releasing him. I think the second pic looks like a o> but the only thing I'm sure of is that I'm not sure lol. He/she also has a lot longer and sharper fins than his/her siblings did but that doesn't really mean anything with argenteas since both sexes get long streamers eventually. I'll take some more vent shots when this fish is larger. I don't know if I'm going to keep this guy/girl permanently but it sure is a nice little fish. I'll put up some pics soon.
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