Female masked swallowtail angelfish

[wei15986]

Female Masked Swallowtail Angel Developing Male Coloration Despite Having a Male?


I currently have a pair of Masked Swallowtail Angelfish (Genicanthus semifasciatus) in my Waterbox reef tank, and I’ve noticed something interesting.


The female was introduced first, followed by a larger male. They’ve been living together for approximately 1.5 months.


Fish details:

• Male: approximately 5–6 inches
• Female: approximately 3 inches
• Tank: Waterbox Frag 125.4
• Both are eating normally
• No obvious aggression between the pair

The male occasionally displays toward his reflection, but I haven’t seen him actively chase or attack the female.


Recently, however, I’ve started noticing some yellow coloration or thin yellow lines developing near the female’s facial mask.


This has me wondering whether she might be starting to develop male coloration even though there’s already an established male in the tank.


My questions:

1. Can a female Genicanthus semifasciatus begin transitioning toward male coloration while living with an established male?
2. Is the presence of a dominant male usually enough to suppress sex change?
3. Could the yellow facial markings simply be part of normal female maturation?
4. Has anyone successfully maintained a male/female pair of this species long-term?
5. What behavioral changes should I expect if they are establishing a stable pair?

I’ve read about protogynous sex change in Genicanthus angelfish, but I’m particularly interested in real-world observations involving this species.


I’d love to hear from anyone who has kept Masked Swallowtail Angelfish pairs for several years, especially if you’ve observed changes in coloration or social dynamics over time.

 

[Boreas_SA]

Those look like a full female and a transitioning female to male. Do you also have another male in the tank (as you said you have a pair)?