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Rainbows... Anatomy question

captmicha

Members
My two rainbows were circling each other the other day and there was a reproductive organ visible. But how do you know if it's a cloaca or... a penis?

IMG_2866.JPG

IMG_2869.JPG
 
In my experience, the boys are bigger and have fancier fins with trailers. I've not been too studious about their privates! :)
 

Frank Cowherd

Global Moderators
Staff member
From the internet, A cloaca is a common cavity at the end of the digestive tract for the release of both excretory and genital products in vertebrates (except most mammals) and certain invertebrates. Specifically, the cloaca is present in birds, reptiles, amphibians, most fish, and monotremes.

So since rainbow cichlids are fish and are not livebearers, what you see is a cloaca. However, in egg laying fish most of the people I talk with refer to the visible organ as an egg duct or ovipositor and it is very visible on a female about to lay eggs and not visible when she is not about to lay eggs. The males have a similar but much smaller one for sperm and it is probably called something else, but I do not know what. Though there will likely be some suggestions after this is posted.

The internet defines ovipositor as a tubular organ through which a female insect or fish deposits eggs.
 

chriscoli

Administrator
from the picture you posted, it looks similar to what I've seen on the females. That being said....there's always a chance it's not.
 

Frank Cowherd

Global Moderators
Staff member
If your just want to know if you have a male or a female, then the ovipositor makes the answer fairly easy. Females never have their ovipositor visible unless they are about to lay eggs, even if there are no males in the tank. If it looks large enough for an egg to pass through, the fish is a female. Males never have their whatever out unless a female in the same tank is ready to spawn and their ovipositor is thin relative to the females. If you only have males you will probably never see their spawning apparatus unless there is a female ready to spawn. If you have only females, all the apparatus will be about the same size.
Hope that helps.
 

Becca

Members
It's an ovipositor...

Just to take this further off the rails, reptiles have hemipenes... there's an organ on each side, just inside the cloaca, rather than just one.
 
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