Swallowtail pair both Females?

[sawdonkey]

I’ve had a pair of swallowtails for well over a year. When I got them, the bigger one had faint tiger stripes of the mail patten. Over time, those stripes have faded to the point of barely being able to see them. His behavior is definitely dominant since he chases the other one around fairly frequently. Is there something keeping him from going fully male?

 

[Jay Hemdal Verified Community Expert]

I’ve had a pair of swallowtails for well over a year. When I got them, the bigger one had faint tiger stripes of the mail patten. Over time, those stripes have faded to the point of barely being able to see them. His behavior is definitely dominant since he chases the other one around fairly frequently. Is there something keeping him from going fully male?

I’ve had a couple of Genicanthus change from male to apparent female over time. Oddly, other species such as anthias and bird wrasse seem to change to males more often. I dimly recall something called exogenous hormones, in the tank water, that can effect sex determination in fish, set the pecking order in discus, etc.

Jay

 

[mort]

It's not uncommon with genicanthus to show the beginnings of male characteristics and then revert back. They are a genus that doesn't readily change sex in aquaria from most of what I have read over the years. It's also possible for them to begin the change and then just stay in the middle, showing characteristics of both male and females.

 

[OrionN]

Over the last 30 years I keep about 6 Watanabei angels. Although I never bought a male, I always have a male in the tank. One of mine always change from female to male.
Other than the two, do you have any other Genicanthus angel in the tank? If you have a more dominant Genicanthus, he may keep your swallowtail from fully change.
Here is my pair. I no longer have this pair. My tank crashed in the aftermath of hurricane Harvey. RIP

 

[sawdonkey]

Over the last 30 years I keep about 6 Watanabei angels. Although I never bought a male, I always have a male in the tank. One of mine always change from female to male.
Other than the two, do you have any other Genicanthus angel in the tank? If you have a more dominant Genicanthus, he may keep your swallowtail from fully change.
Here is my pair. I no longer have this pair. My tank crashed in the aftermath of hurricane Harvey. RIP

Those are great fish! No, no other angels in the tank. However, I do have other aggressive fish (two triggers and a large eel). Could the other species keep them from becoming fully dominant?

 

[Zionas]

Very pretty!

I wonder if two females would fight?

 

[OrionN]

Two females will not fight

 

[sawdonkey]

Well, it’s 2.5 years later after my post above, and both of my fish are still females. They chase each other around some, but neither seems dominant. I think I have no chance at one turning male.

They are bother super mean to new additions to the tank. I recently tried to add a bristletooth and a sailfin, and the angels were super aggressive to them. Much more than my triggers!