Apisoto Cacatuoides sexing help

[Crazy_Bee]

Hi guys, can anyone verify if the pair that I got is indeed a male-female pair? The one I'm having trouble with is the supposed female, which is sightly smaller than the male. She's also not as yellow as normal females I see on the internet. Got this pair yesterday from 328. The male has also been chasing her around the tank.
Supposed-female on the left, Male on the right.

[seudzar]

Don't look female to me... still a bit small to tell. Look out for top fin and tail fin growth... if the tail fin turns out to be long and pointed. It's a male

[boofeng]

Fins look very colourful for a female - I'm not familiar with domestic morph cacatuoides though.

Among apistos and many other fish, non-dominant "sneaker" males can to some extent suppress the full development of visible male traits when there is a lack of territory for them to establish dominance. If you have time and a spare tank, consider growing the supposed female there, isolated from the other apisto, for a month or two? That's usually enough time for males to "reveal" their dominant traits (extended fins and typical male colours).

However, without the luxury of time, just look out for the dorsal, anal and tail fins. In a domesticated morph I can't be sure, but among wild form apistos, extended, trailing soft rays at the rear of the dorsal and anal fins usually indicate maleness. The development of extended 2nd, 3rd, 4th hard rays on the dorsal is also a male trait. And the tail is even more of a giveaway - if it starts forming a "lyre" structure, that's a male. Females have "fan" shapes, like juveniles. But remember, lack of evidence doesn't mean it's male - it could very well be a "sneaker", or a young fish.

If you have enough hiding places, decent water conditions, and it's a female, it should spawn soon. That's the best proof! BTW, the strong yellow colours you see on the internet are probably females guarding eggs or fry. They turn a bright yellow and black when doing that (a good way to know you have babies, even if they're hidden in a cave or crevice!)

[tommygro2]

looks too colourful for a female, i would say it is a male.