Is my betta a female?

[Aurorae]

I recently picked up a female betta from a pet store, and I've noticed something pretty interesting - her fins have grown incredibly long in a really short amount of time. Compared to the female bettas I've had in the past, hers are definitely longer. It's got me wondering, could she actually be a male that the pet store misidentified?

I've included some pictures for reference - the bottom two are from when I first brought her home, and the top one is from about two months later. You can see there's been a bit more fin growth since then.

[coltin]

Your betta's fin growth does seem quite extensive, which is unusual for a female. To confirm its sex, you might want to take a closer look at the ovipositor, the tube it uses to lay eggs and also poop from. If it's white, it's likely a female, but if it's dark, that would suggest it's a male.

[sSjey]

I'm inclined to agree it's a male too. Try holding a mirror up to see its reflection, that usually gets a reaction. Females can flare just like males, so that alone isn't a definitive sign. If it does flare, take a closer look at the Sprig - if they extend all the way under the head, like a beard, that's a good indication it's a male.

[Aurorae]

I'm having trouble locating the ovipositor, and I'm pretty sure I'd notice a white spot on a black and red fish. I've tried to get a flare going but no luck. My tank already has a mirror back, so my betta is used to its reflection. If this does turn out to be a male, will having the mirror there cause him too much stress?

[earthie_9]

No doubt in my mind, this is a male betta. The pelvic fins are a dead giveaway - they're full, long, and have those distinctive white tips. I've never seen a female with fins like that. It's not like it's unheard of for pet stores to misgender their bettas, either. I've had it happen to me twice with "baby bettas" from Petco, and honestly, it was no big deal.

[coltin]

If the ovipositor area is dark, it's likely a male. A white spot would be fairly noticeable, especially on a black and red fish.

It's generally recommended to limit mirror exposure to short periods, say 10-15 minutes a couple of times a week. This allows the male to feel like it's successfully chased away a rival, giving it a confidence boost.

[goldminer]

No doubt about it, that's a male betta.

[Aurorae]

I suppose a name change is in order. Given the tank's design, removing the mirror isn't an option, so I'll have to rearrange some things to minimize the impact.