How Do You Tell The Difference Between Female Mollies And Swordtails

[sherylp]

Hi, I'm new here to the forum. My son has had fish for a couple of years now and got bored with them and didn't want them anymore. So I bought myself a bigger tank and moved his fish into my tank. I have since bought a few more.

I have some Swordtails and some Mollies. I know which are which by what they were when I bought them, however, from what I can tell I think three of the females have had fry over the last week. The Swordtail female had fry and 2 of the mollies.

They had the fry in the main tank and there are tonnes of places for the fry to hide, we see them come up every now and then so we know there are survivors. The problem is that I really don't know how to tell the difference between these 2 species, so when these fry get older I may have trouble distinguishing between swordtails and mollies.

Is there any easy way to tell the difference?

I also have one more Mollie that I've just put into a breeder box because I'm pretty sure she is about to drop. Although I'm no expert and still have trouble determining if they are ready to drop or not.

 

[Rummynose]

I had a similar problem last week at the LFS, there was a tank labelled dalmation molly, and another tank labelled assorted platies, in which was a dalmation "platy". The mollies looked like platies to me, lol!

 

[Dieses Madchen]

Look at the fins, swordtail fins are more squared, and the molly's are more rounded.

 

[sherylp]

Look at the fins, swordtail fins are more squared, and the molly's are more rounded.

Ok thank you. I don't see a big difference between the fins on my mollies and my swordtails - maybe a little toward the back of the fin. I will have to study them a bit more so I can get to know the difference.

 

[lilfishie]

only male swordtails actually have the sword, i find mollies tend to be deeper bodied than swords, there fry are also born considerably bigger than most other livebearer fry.

i will try get some pics of my mollie fry and swordy fry to show you the difference

 

[OldMan47]

Welcome to the forum sherylp.
I always go by head shape and body lines. A swordtail has a far more streamlined looking body. The molly will have a mouth positioned almost as if it was meant to skim the water's surface while the swordtail's mouth will seem more centered.

 

[sherylp]

only male swordtails actually have the sword, i find mollies tend to be deeper bodied than swords, there fry are also born considerably bigger than most other livebearer fry.

i will try get some pics of my mollie fry and swordy fry to show you the difference

Aaahhhh that will explain why the little black fry I spotted looked like it was 2 or 3 weeks old (mollie I believe) compared to the little swordtail fry who are tiny.

Thanks

Welcome to the forum sherylp.
I always go by head shape and body lines. A swordtail has a far more streamlined looking body. The molly will have a mouth positioned almost as if it was meant to skim the water's surface while the swordtail's mouth will seem more centered.

Thanks, I will take a closer look at the mouths - hadn't really noticed much difference there so will look closer. I did notice my swordtails did look more streamlined than my mollies but wasn't sure if that varied.