Betta sex

CassCats said:

I'd like to lean male, but if you can get a better picture where the side of the body is well lit, so I can look at the body cavity shape?

Males have a rounded shape body cavity while females have a long, pointed body cavity due to their ovaries.

Koi females can be just as vibrant and large as males, so it can be tricky with these colors.

I don't rely on presence of "egg spot" as I've had males have egg spots in the past, I don't find it as accurate as the ovaries vs no ovaries deal.

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Colin_T said:

Look at the ovipositor (egg laying/ poop tube). Females have a white ovipositor, males have a coloured one.

Males develop a black beard (flap of skin around the lower edge of the gill covers), females don't have this.

Put a mirror next to the tank and see if the fish flares its fins out and tries to kill the reflection. If it does, then it's probably a male.

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CassCats said:

@Tyler777 I fixed up lighting and did a backlight fix, but in a couple views, it looks like she's got a triangular shape to the body cavity. This coincides to the shape and location of betta fish ovaries on a female. Males will never have this triangular shape because they do not have ovaries.


View attachment 357394

outlining the triangle shape I see on the fish with a white line.
View attachment 357395
I've had male bettas with "egg tubes" and were without a doubt male. The egg spot is not 100% so I prefer to go by the body cavity method because it is more accurate.

It's harder to see ovaries on darker colored fish, but if you know what you're looking for, you can see it.


With this, I'd actually lean towards this being female.

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Tyler777 said:

You are a scientist, my respect to your knowledge. Even if she is female she is too aggressive towards the others. We got 5 females that day including this one n 2 days later 3 were dead, for some reason she likes the surviving one but she still bullies her but didn't kill her.
Yesterday we put her in a cup to take her back to petsmart so we got a beautiful female that was red, white n blue. But these 2 we have we both chasing her n bite her so we have to rescued her n we took her back to petsmart.
So we put the bully into a cup n let the other one loose so yesterday we got 5 more girls n the one loose on the tank went crazy chasing the other ones non stop so into a cup she went too. Tomorrow we r gonna take em both back n get 2 new ones. All the new ones get along without any problem those 2 bullies seem to be the problem.
BTW we saw some king something males that were 5 inches long, they were huge. Never seen a male that big.

Thank you again for all your help n knowledge.
God bless

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CassCats said:

@Tyler777 I fixed up lighting and did a backlight fix, but in a couple views, it looks like she's got a triangular shape to the body cavity. This coincides to the shape and location of betta fish ovaries on a female. Males will never have this triangular shape because they do not have ovaries.


View attachment 357394

outlining the triangle shape I see on the fish with a white line.
View attachment 357395
I've had male bettas with "egg tubes" and were without a doubt male. The egg spot is not 100% so I prefer to go by the body cavity method because it is more accurate.

It's harder to see ovaries on darker colored fish, but if you know what you're looking for, you can see it.


With this, I'd actually lean towards this being female.

Click to expand...

Tyler777 said:

You are a scientist, my respect to your knowledge. Even if she is female she is too aggressive towards the others. We got 5 females that day including this one n 2 days later 3 were dead, for some reason she likes the surviving one but she still bullies her but didn't kill her.
Yesterday we put her in a cup to take her back to petsmart so we got a beautiful female that was red, white n blue. But these 2 we have we both chasing her n bite her so we have to rescued her n we took her back to petsmart.
So we put the bully into a cup n let the other one loose so yesterday we got 5 more girls n the one loose on the tank went crazy chasing the other ones non stop so into a cup she went too. Tomorrow we r gonna take em both back n get 2 new ones. All the new ones get along without any problem those 2 bullies seem to be the problem.
BTW we saw some king something males that were 5 inches long, they were huge. Never seen a male that big.

Thank you again for all your help n knowledge.
God bless

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Tyler777 said:

One of my female koi bettas had some fuss growing on her face. U know what that is ?

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JohnnyReb said:

As far as sex goes, does it have long flowing ventral fins? I think you will have a hard time starting a sorority that way. As far as the 5 inch male, did you measure it and was it in one of those magnified cups the pet shops use, to make them look biggggger. The term King and Giant are thrown around loosely by pet shops. If it was 5 inches, it was a Giant and maybe one of a very few that size in the U.S.??

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