# how long?



## FeederFish33 (Jan 22, 2003)

How long until my piranhas reach 6 inches? They say thats how big they should be to feed them mice. They are 3.5 to 4 inches. There are 5 of them in a 55 gallon tank. The water temp is 81, the ph is 6.9. I feed them shrimp, pellets, and krill. How long will it be before they hit 6 or more inches?


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## Grosse Gurke (Jan 3, 2003)

Tough question. Could be 2 months, could be a year. I have a red that about 4.5" and he is not growing much at all and I have another red that I got at the same time, same size, that is about 6" now, so I believe there is an element of genetics tossed in.


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## FeederFish33 (Jan 22, 2003)

i got 4 of them from on guy, and 1 other from another guy. The 1, I call him rambo because his spots are a lot darker and look like camoflage, has much bigger teeth and one eye is like inside its head instead of out. Its hard to explain, but the other ones have eyes that bulge a little, and this one has one eye that is deep in its head. I dont understand what it is.


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## Genin (Feb 4, 2003)

I agree with grosse gurke on this one. Genetics does seem to play a factor. I have never had all of my fish grow at exactly the same rate. There always seems to be a big guy and a little guy of the shoal. I am getting a tremendous growth rate of out my boys and I hope to have mine at six inches by the end of this semester. Good luck with Rambo and the others.

Joe


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## Outie (Feb 19, 2003)

I also agree with everyone else, it really depends on the fish, out of the 6 i bought as babies, about 4 of them grew really well, while 2 are growing at a much slower rate. But the funny thing about it is that the 2 smaller ones have attitudes and will actually beat on the larger ones.


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## RhomZilla (Feb 12, 2003)

True, each fish has its own genetic inclination. Also what you need to do is get a bigger tank. Im not trying to school you on 1 fish per gal. But no matter what type of fish, they all adapt to their environment.. the bigger the space the faster the growth rate.


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## bobme (Feb 17, 2003)

well i cant tell you more then the rest of us here, however yes it depends upon many things, that i dont think we can tell. genitics and others. However proper feeding and a larger then normal tank would help them grow to their fastest rate that the fishes genitcs will let them grow to.
hope that helps some.


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## Bola (Feb 24, 2003)

When fish you got at the same time at the same size later have a noticeable size difference, the smaller, feistier ones are the males and the bigger ones are the females. Oops, sorry, didn't mean to get that debate stirred up again. Sorry Frank and Nate, but that is my hypothesis, unconfirmed by any scientific evidence.


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## hastatus (Jan 16, 2003)

> Sorry Frank


 Nothing to be sorry about. Have you PM'd Xenon yet to add your name to the list of those wishing to test this _hypothesis_ out of being able to tell males from females using size as a factor?


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## thePACK (Jan 3, 2003)

hastatus said:


> > Sorry Frank
> 
> 
> Nothing to be sorry about. Have you PM'd Xenon yet to add your name to the list of those wishing to test this _hypothesis_ out of being able to tell males from females using size as a factor?


 just wondering when is this suppose to happened...and i know this ain't the forum but has there ever been a study of growth rate between female and males from 1" and up... thanks frank


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## hastatus (Jan 16, 2003)

> just wondering when is this suppose to happened


 It will happen soon. Cutting up several piranas accurately is time consuming and nothing to be rushed because of the organs below. Also I need to take several photos before and after to use so that no excuses can be used that the picture was not clear enough. Be patient, those that think P. nattereri are sexually dimorphic will have their chance to prove it.



> but has there ever been a study of growth rate between female and males from 1" and up... thanks frank


 There has, but many factors are indicated to not use this as carved in stone. Individuals grow at different rates.


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## WebHostExpert (Jan 16, 2003)

I have been documenting the growth of my red bellys since birth, and can say they have reached 6-7"s in 8 months. I am now starting to document the growth of spilo's from birth. I will let everyone know when the research is complete. but unfortionatly wont be for a couple years.
MAD


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## hastatus (Jan 16, 2003)

> I have been documenting the growth of my red bellys since birth, and can say they have reached 6-7"s in 8 months.


 I hope you are keeping accurate counts and morphology information on all of them and not just generalizing for the entire group?


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## SnowCichlid. (Jan 10, 2003)

hastatus said:


> > I have been documenting the growth of my red bellys since birth, and can say they have reached 6-7"s in 8 months.
> 
> 
> I hope you are keeping accurate counts and morphology information on all of them and not just generalizing for the entire group?


 I have also read some articles were RBP's will grow from just out of the egg to 5 inches in 8 months. Would this be considered a normal rate, If so then what he has done would be more of an accomplishment then


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## WebHostExpert (Jan 16, 2003)

> I hope you are keeping accurate counts and morphology information on all of them and not just generalizing for the entire group?


humm dont know what that means. but hey whatever I dont have to share, was just trying to help, if you want to tell me what information I should be keeping my ears are open.
MAD


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## SnowCichlid. (Jan 10, 2003)

MAD piranhas said:


> > I hope you are keeping accurate counts and morphology information on all of them and not just generalizing for the entire group?
> 
> 
> humm dont know what that means. but hey whatever I dont have to share, was just trying to help, if you want to tell me what information I should be keeping my ears are open.
> MAD


 I do believe he is asking what are the specific growth rates of each individual fish and at what times did each indiviudal fish start making what changes


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## WebHostExpert (Jan 16, 2003)

There is no way I could keep track of 41 piranhas in one tank. So just forget it.
MAD


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## hastatus (Jan 16, 2003)

> There is no way I could keep track of 41 piranhas in one tank. So just forget it.


 The idea was to benefit you and everyone else to get a better handle on what I was meaning about piranas developing distinctly from each other. It was not meant to disprove anything you wrote. However, if you are unable to keep such records (and it is understandable) no problem. Thank you for bringing up this interesting topic. If you change your mind, let me know via PM, perhaps we can devise something to help this out.


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## WebHostExpert (Jan 16, 2003)

done, you have mail.
MAD


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## hastatus (Jan 16, 2003)

> done, you have mail.
> MAD


 And all is being answered!


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## x-J-x (Nov 28, 2002)

Don't know...I got my reds when they were 1" and that was last september...now they are 6"


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## thePACK (Jan 3, 2003)

x-J-x said:


> Don't know...I got my reds when they were 1" and that was last september...now they are 6"


 how big of a tank do you have them in?


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## Bola (Feb 24, 2003)

Sorry, been off the board for a couple days, but to respond to your question Frank, no I do not wish to add my name to the list for the experiment. First, because I agree with you that nattereri are not sexually dimorphic, at least in any relevant, easily identifiable way. I do have an opinion that if age, genetics and diet are controlled for that females will be noticeably larger at maturity, all those other variables being equal. This is true of many fish species, at least some of the North American ones I am familiar with, the walleye being one example. Of course this is irrelevant from a scientific point of view, at least in wild populations, because those variables can never be controlled. I would think it would be testable in captive bred populations if you have known parentage, the same batch of fry raised together in the same aquaria with the same diet being fed, grown to maturity then postmortem studies being done comparing size and sex. I think under these conditions, and these conditions only that size would be a statistically relevant determinant of sex, or vice-versa. Again, my unscientific opinion only.


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## hastatus (Jan 16, 2003)

> I do have an opinion that if age, genetics and diet are controlled for that females will be noticeably larger at maturity, all those other variables being equal.


 If only it were that simple then culling of males from females using microscopic exam of larvae sexual organs would not be needed to determine sex for scientific lab tests. Your presentation is very well thought out. Thank you.


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## x-J-x (Nov 28, 2002)

thePACK said:


> x-J-x said:
> 
> 
> > Don't know...I got my reds when they were 1" and that was last september...now they are 6"
> ...


 They are in 55gl...feed them 3 times a day...w/ different variety...krill..shirmp...feeders...beef...brime shrimp


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## Bola (Feb 24, 2003)

hastatus said:


> > I do have an opinion that if age, genetics and diet are controlled for that females will be noticeably larger at maturity, all those other variables being equal.
> 
> 
> If only it were that simple then culling of males from females using microscopic exam of larvae sexual organs would not be needed to determine sex for scientific lab tests. Your presentation is very well thought out. Thank you.


 Frank,

Thanks for the respose. You lost me however on the culling statement. Could you elaborate on that a little further? Fascinating to me.


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## hastatus (Jan 16, 2003)

> You lost me however on the culling statement.


 = separate by size or sex (specific).


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## Bola (Feb 24, 2003)

So if I understand correctly, the only reliable way to sex nattereri which has been found is dissection and microscopic genital examination. 4 follow up questions:

1. Do I understand correctly?

2. Has anyone tried to see how well (if at all) size at maturity correlates with postmortem microscopic sex determination, especially under the controlled conditions I described?

3. If this has not been tried, what is your educated opinion on what the results would be?

4. Is this essentially what the upcoming experiment is designed to answer?

Thanks again Frank.


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## hastatus (Jan 16, 2003)

> Thanks again Frank.


 replies are in a PM to you. Enjoy


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