# Blue Dolphin Sexing



## jcolella1 (Oct 16, 2012)

I have a group on blue dolphins and was wondering if anyone here can help telling if they are males or females. They are between 3-4 inches. All have great blue color, eating well and growing quickly. I have read that you can tell by the length of the anal fin but wanted some other opinions.
Thanks


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## jcolella1 (Oct 16, 2012)

Here are some better pics.


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## nmcichlid-aholic (Mar 23, 2011)

jcolella1 said:


> Here are some better pics.


Judging from fin shape/size alone, this one might be a male, but the rest all look like females to me. Obviously, there are other factors that would help determine gender as well, like the individuals behavior within the group, but venting is the only sure way to tell. Generally speaking, though, I have usually been able to pick out males based on fin size and shape at around 3", and it is usually much more obvious than this one is. If he is the dominant one in the group, I would still say male, though.


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## jcolella1 (Oct 16, 2012)

Thanks for the response. I guess the only way to know for sure is venting. I've never done it but I guess there's a first time for everything.


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## Chromedome52 (Jul 25, 2009)

They are all females. The anal fin is the key to sexing _Cyrtocara moorii_. Note that all the fish have the lower edge of the anal curve up to the rather blunt point. Males have an edge that is straight back to the point, and as they mature that point grows downward and longer than the female. I've sexed them at 2.5 inches based on this technique, Which was shown to me by one of the first Florida commercial breeders to produce this species, over 35 years ago.

I would note that it is unusual to have extra females, most people end up with more males.


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## jcolella1 (Oct 16, 2012)

This would be great. I have a tank with some smaller moorii and one I am almost positive is a male. It chases every other fish in the grow out relentlesly. Its only about 2 inches, which is the reason its not in this tank. If you are correct I am a happy person! Thanks.


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## jcolella1 (Oct 16, 2012)

I tried venting for the first time today. All I saw was one large opening, not two. I read that males will have two small openings & females will have one large and one smaller. Does this mean the second opening was smaller & is female? Like I said, it was my first time ever venting. I read a number of articles and saw the pictures but I didn't see anymoorii.


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## nmcichlid-aholic (Mar 23, 2011)

Venting can be tricky, especially with young fish that haven't spawned yet. It is difficult to get a good look at a fish's underside when they are wet and squirming, so a helpful hint is to ask a friend or a very understanding spouse to take a close-up photo with a good digital camera while you hold the fish. This will allow you more time to study what you're looking at, and even zoom in. You can also post the photos here for second opinions.


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## aicardi (Sep 15, 2012)

nmcichlid-aholic said:


> Venting can be tricky, especially with young fish that haven't spawned yet. It is difficult to get a good look at a fish's underside when they are wet and squirming, so a helpful hint is to ask a friend or a very understanding spouse to take a close-up photo with a good digital camera while you hold the fish. This will allow you more time to study what you're looking at, and even zoom in. You can also post the photos here for second opinions.


This is exactly how I do it. Less time the fish is out of water and one can study the image.
My guess is that if you see one big opening then it is most likely female.
Samples of my venting of 2" Socolofi. 
Female: vent on left. Anus on right. Oo









Male: vent on left. Anus on right. oo


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## jcolella1 (Oct 16, 2012)

Thank you all for your help.
I vented and looks like I have 4 females & 1 male. Couldn't ask for a better grouping. Looking forward to these breeding in the future.


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## Ogom (Sep 13, 2012)

http://s1337.beta.photobucket.com/user/ ... sort=3&o=1

http://s1337.beta.photobucket.com/user/ ... sort=3&o=0

Hi guys,
after reading this post I also tried to sex my Malawi dolphins. I bought them less then 1 month ago, I bought 6 in order to have at least one male and 2 females. I came to realize 5 of them have the anal fin much shorter the the 6th one which is the smallest of the group. He should be the male but the girls bully him a bit. I attach a couple of pictures and if somebody can confirm I thank him/her in advance. The male , if it is a male, it is much darker and much smaller in size.


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