Sexing Rivulatus

[asm129]

I think the 1st one is male because of the bright body colors. The 2nd one looks female to me because there are two vertical white lines on the body like a female would have and the body colors are duller than the 1st GT. The 3rd one, seems like a subdominant male because the colors are even and brighter than the 2nd one. I think if you took out the alpha male, he'd color up a lot more. The 4th one seems female to me because of the two vertical white lines like the 2nd one has and the colors aren'tbright throughout the body like 1 and 3. So 1 and 3 look male and 2 and 4 look female to me.

Good luck. Good group of GTs you've got there.

 

[tiger15]

Vertical white stripes and black beard can show up in juvenile and subordinate males, so they are not sure sign of females. I don't notice blue face in female GT as in female JD as one poster noted. However, breeding female GT darkens up and the white stripes and black beard are accentuated. Breeding male and non-breeding female GT brighten up and the white stripes disappear and the the beard becomes less obvious. So non-breeding females are actually more colorful than breeding females as in many CAs. Sexual dimorphism becomes more obvious with size above 5 inch and sexing is easier as males outgrow females, show brighter color and longer trailing fins.

 

[Manu8__too]

1. Male
2. Female
3. Male (subordinate)
4. Female

I'd bet money on it. Bearding on GT's to determine gender is 100% irrelevant. Both males and females can exhibit bearding in this species. Color, shape and fin reticulation are viable factors when differentiating gender. As for breeding dress, the poster above is correct. Females drastically darken and display two vertical cream colored bars.


Sent from my iPad using MonsterAquariaNetwork app

 

[notho2000]

Vertical white stripes and black beard can show up in juvenile and subordinate males, so they are not sure sign of females. I don't notice blue face in female GT as in female JD as one poster noted. However, breeding female GT darkens up and the white stripes and black beard are accentuated. Breeding male and non-breeding female GT brighten up and the white stripes disappear and the the beard becomes less obvious. So non-breeding females are actually more colorful than breeding females as in many CAs. Sexual dimorphism becomes more obvious with size above 5 inch and sexing is easier as males outgrow females, show brighter color and longer trailing fins.

I agree with 'Manu8__too' assessment based on the pictures. Tiger15 makes some valid points too. However,once they mature, the blue beard on the females becomes really apparent. Here's pics of a female (1st three) and male (next three), once mature.



female




male

 

[tiger15]

Here are pics of a male, a non-breeding female, a non-breeding pair, and a breeding pair in sequence. Note that the female does not show much white stripes nor the beard until she puts on the breeding dress in the last pic and in the youtube when the pair is guarding fry. The female darkened in breeding dress, and the beard and white stripe come and go, but the male hardly changed except for showing a faint beard.
https://www.youtube.com/watch?v=mCY-2y9dIJI

 

[desmo_lover]

Thank you everybody for your answers!
So I have to wait, hoping that I could early observe a breeding pair in my tank..
I'll of course keep you informed of further developments!