How To Absolutely Be Sure Your Betta Is A Girl/Boy

How To Absolutely Be Sure Your Betta Is A Girl/Boy

I've noticed something interesting. Wild Bettas (all 73 species) can easily be identified because of sexual dimorphism, meaning females are rounder, duller, have shorter fins and egg spots compared to males that are generally much more colorful and aggressive with longer fins. However, because of selecting breeding, it has become increasingly harder to tell them apart. Luckily, I've recorded my findings over the past decade! Here's how to find out:

1. Both males and females flare and are territorially aggressive.

2. Although it is rare, females can blow bubble nests too! I actually recently adopted out a girl who did.

3. Because of selective breeding, females can have long fins and vibrant colors. On the contrary, males can have dull colors and short fins! It all depends on genes (though we won't get into all that jazz!)

4. Young males sometimes have false egg spots to increase their chance of survival (a wild evolutionary trait), which can be seen up until around 18 months.

5. Females are the same size as males. Standards have a body length of 1.75 to 2.25″ (4.4 - 5.7 cm), Dwarves are 1.25 to 1.5″ (3.1 - 3.8 cm), Runts are the same size as Dwarves initially but grow to full size around 6 months late compared to Standard, Half-Giants are 2.5 to 3″ (6.3 - 7.2 cm), and True Giants can be as large as 6″ (15.2 cm)! Many have never heard of Giant and Half-Giant females but they do exist and are the same size as their male counterparts.

7. Both are candidates for community tanks but it depends on how they're raised, the temperaments of their parents, and individual personality. Most have no idea of their pet's background so it can be a gamble to find the right community-suitable Betta whether they be female or male.

8. Females generally have a rounder belly compared to males, however that can also be due to bloating, Dropsy, internal parasites and obesity (we'll get into diet and proper feeding in another thread).

9. Both males and females have "beards", part of the gill sticking out from the bottom of their face, but it's generally much longer in males.

As you can probably tell by now, it can be difficult to sex Bettas unless you have an knack for it. In my experience, there is only one true way to tell; if you see a large, whitish-yellow, triangular shape on the belly, it's absolutely female since this is where she carries her eggs. But even this can be hard to spot since most Bettas are iridescent.

"So then how can I tell if my Betta is a boy or girl?" Check all of the obvious signs first, of course! Excessively long and ruffled fins means he's probably male. A rounded belly and not-as-lean look means she's probably female. A large egg spot especially over 18 months of age means she's definitely a girl! Big beard? Definitely male. Just don't use flaring, bubble nests, or aggression as a surefire way to tell.

I hope my explanation is easy to understand and helps you identify whether you have a female or male! Feel free to comment and good luck ;)


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Amazing article! My only critique is to maybe add some pictures or what your talking about, beard, egg spots, etc. Thanks for the great content!!
Thanks! I'll be editing the article soon! And you're right, I'll add pictures :)
  • AIvinn
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This article was informational and grammatically well-written! However, the only critique I'd give is to organize your articles into sections rather than a list, especially when you're comparing two things. (:
Thank you alvinn!! :D
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