Sexing baby Betta

[NYUguy91]

I bought a baby betta today at Petco and set up a pretty thorough one gallon tank for it. I've been researching sexing baby Betta fish and am having a hard time. It's about half an inch long and has dark horizontal lines. The coloring is blue, but doesn't look as vibrant as on adult males. The body shape seems very thin and long, even thinner and longer than in this photo. Any ideas?

 

[Taari]

1/2 inch betta fry are only a few weeks old. Often they can't be sexed until around 2 months old, and even then it can be iffy. Keep it's water clean and feed it well and you'll probably be able to tell for sure in a few more weeks.

 

[BettaFishMommy]

most big box stores do not sell bettas that young. customers don't want juvenile fish that have less colour and less finnage. your betta looks larger than 1/2 inch, more towards 1 inch or maybe a bit bigger.

i would hedge a bet that your betta is female, and is very very stressed. those horizontal lines are called 'stress bars', and show more easily on females than males. her colour will come in as she gets bigger/older. baby fish are not coloured up like adults because they are easier food targets for larger fish. the 'blander' the fish looks, the easier it can hide from predators while it grows into an adult fish that can more easily defend itself or get away.

the fool proof indicator on male or female is on the underside of the betta, between the ventral fins. if you see a small white nub, then you have a female. this is the ovipositor, part of the female reproductive anatomy.

 

[NYUguy91]

I've been checking around and read that many baby betta fish of both sexes display horizontal lines in their youth, that are not related to stress, so I'm hoping that's it. But I did just move him/her into a new tank so stress is a definite possibility.

Did a vague measurement of my new Betta at the surface and it appears to be a little under an inch. I tried checking for an egg spot but had difficulty. It's quite a feisty fish and doesn't like staying still haha. It also seems to be making bubbles on the surface that aren't staying. I know this is usually a mating behavior in male bettas, but still leaning towards female in ID.

I guess we'll see for sure in a few weeks!

 

[BettaFishMommy]

females have been known to blow bubble nests just as well as males can. it is not common, but they can do it.

tip for checking a betta's underside - feed them! after having your betta at home for a while, they learn that the tank lid opening means food time, and they will usually tip their noses up to the water surface as soon as you open that lid. prime time for checking betta undersides.

and just to clarify, you say you set up a 1 gallon tank. this tank has a filter and heater? or your home stays warm enough (76 or higher at all times) to keep the tank warm enough without heater? bettas really should have environments larger than just a gallon. my minimum betta tank size i will ever have is 2.5 gallons, and that's with a 5 gallon filter and live plants.

 

[NYUguy91]

Just thought I'd update y'all on my Betta.She's changed so much! Her (I'm assuming now it's a she) color is extremely vibrant and she's super active. I think I'm in love. As she gets older I'll move her into a larger tank. But she seems to be happy for now. Here are a couple of horrible photos I took of her. She moves so much it's hard to get a good pic.


Do y'all think it's a girl as well?

 

[NYUguy91]

So... My baby has grown so much! Her (I'm now assuming it's a girl, but who knows) coloring is absolutely beautiful. Blue fins, black head with blood red ventral fins. She's seems extremely happy and she's very active. When she gets a little bigger I'll move her into a bigger tank. I've attached two more recent pictures. Let me know if you agree with the sexing.


P.S. Sorry for the horrible quality of the photos. She's just too feisty to get pictures of.

 

[BettaFishMommy]

i would move her to a larger tank now, with a filter and heater. she doesn't have to be fully mature to enjoy a larger and better environment, and moving her now will be the best thing for her.

without the confirmation of the ovipositor spot (that white nub i was talking about), it is hard to say girl or boy. but the shorter fins and the rounded belly in your most recent shots are still telling me female.

 

[Alistair1989]

I just signed up to say that this is 100% a male fish. There is no doubt about it. I would very much like to see pictures of him from after these were shot. A very lovely royal blue veil tail I must say.

Source: breeding bettas for 10 years