Gravid marks on swordtails

[ckoscak]

Hello, all.

I have one male swordtail and three females. I have read they are likely spawning all the time and when the females are pregnant, they will display a gravid mark.

I have been unable to find out what exactly I should be looking for and where.

How soon after the marks appear will the females give birth?

Thank you.

 

[pinballqueen]

I haven't kept any livebearers other than guppies in a very long time, but I'm fairly certain that gravid females will display a dark place along the back of their abdomen, next to their anus (at least in light-colored fish, not sure how well it shows up on dark specimens). This shows up usually about a week or so before my guppies give birth, and gets larger the closer to their due date. Other species may display in a slightly different manner. (In other words, your experience may vary slightly...)

I've not really paid much attention to that lately, since all my fry turn out to be free food for my crayfish anyhow....