The BIG mystery - How to sex angelfish

catsma_97504

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I have been asked many times this summer to help sex angelfish. So, thought I'd try to explain what has taken me 20 years to learn!

For starters, the younger the angelfish the more difficult it is to sex them! If it isn't bigger than a quarter in body size, don't even bother trying to sex them. You will have a 50/50 chance at getting it right; with luck of the draw being the primary factor in accuracy.

Sexually mature angels are much easier to sex, but these characteristics are not cut and dry. And there will always be an angel to fools you! In fact I have one that after 3 years I still struggle to sex it!!!

Even with all these traits that lean toward one sex or the other, the only way to be 100% sure is to see it breed. When the breeding tubes are out it is usually a piece of cake. Female tubes are very thick and take on more of a squared off shape. Males are very small and come to a point more like a triangular shape.

What characteristics to look for

Here is a list of the characteristics I look for to help determine the angel's sex:

General body shape - Female: round; Male: angular
Head shape - Female: flat, skI slope shaped; Male: forms a hump
Eye/Nose band - Female: flat, inline with forehead shape; Male: develops a ridge at maturity
Dorsals - Female: held slightly backward, in line with the forehead angle; Male: fully erect, forms almost a 90 degree angel with the head bump
Ventrals - Female: tends to hold ventrals closer to the body; Male: held erect, forming a distinct angle with the body
Lateral line - Female: nose tends to be slightly elevated compared to the tail; Male: nose and tail are fairly horizontal

Many of these traits are fairly minor characteristics. But add them all up together and one sex or the other tends to stand out.

This picture is that of my Red Capped KoI angels. These two were mated until the male died. Compare the characteristics and you will see how difficult it can be sexing angels! This is why it took me over 20 years to have a higher than average success rate with sexing them.
 

Matt B

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I can see why its so difficult, I was looking for a particular trait and on some it seems quite pronounced while on another male you can barely tell. Thanks for this!
 
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catsma_97504

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Matt B said:
I can see why its so difficult, I was looking for a particular trait and on some it seems quite pronounced while on another male you can barely tell. Thanks for this!
This could be nothing more than age. That's why I said the younger the more difficult.

Sitting in front of a tank or watching how the fish swims in a video is easier than pictures with some traits.
 

ZeeZ

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catsma_97504 said:
I have been asked many times this summer to help sex angelfish. So, thought I'd try to explain what has taken me 20 years to learn!

For starters, the younger the angelfish the more difficult it is to sex them! If it isn't bigger than a quarter in body size, don't even bother trying to sex them. You will have a 50/50 chance at getting it right; with luck of the draw being the primary factor in accuracy.

Sexually mature angels are much easier to sex, but these characteristics are not cut and dry. And there will always be an angel to fools you! In fact I have one that after 3 years I still struggle to sex it!!!

Even with all these traits that lean toward one sex or the other, the only way to be 100% sure is to see it breed. When the breeding tubes are out it is usually a piece of cake. Female tubes are very thick and take on more of a squared off shape. Males are very small and come to a point more like a triangular shape.

What characteristics to look for

Here is a list of the characteristics I look for to help determine the angel's sex:

General body shape - Female: round; Male: angular
Head shape - Female: flat, skI slope shaped; Male: forms a hump
Eye/Nose band - Female: flat, inline with forehead shape; Male: develops a ridge at maturity
Dorsals - Female: held slightly backward, in line with the forehead angle; Male: fully erect, forms almost a 90 degree angel with the head bump
Ventrals - Female: tends to hold ventrals closer to the body; Male: held erect, forming a distinct angle with the body
Lateral line - Female: nose tends to be slightly elevated compared to the tail; Male: nose and tail are fairly horizontal

Many of these traits are fairly minor characteristics. But add them all up together and one sex or the other tends to stand out.
Thanks! Judging from the characteristics you stated, I think my Marble Angel is a female. Her dorsal fin's always kept back at an angle. The other descriptions are more difficult to discern.
 

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