Anyone know anything about gambusia?

[Missa]

Does the black spot on females indicate pregnancy ..... or that they're just females?

[Jerry]

no idea, but you soon will have more than you ever wanted. :'(

[PondmaninAL]

If the "black spot" that you are referring to is the one on both sides, that is the eggs and most likely fertilized. That means that she is pregnant. If you have ever raised guppies or any other live bearer, Gambusia are no different. Sometimes, I think they are born pregnant and you'll find out what I mean soon enough.

[Kat]

I started with 4 & ended up with thousands.  I've finally gotten rid of all of them & now I'm finding I have a lot more goldfish fry since they weren't around to eat the goldfish eggs. 

[Vickie]

I have them in every tub and pond. I give them away to ponders that want some. But then I have a lot of ponds and tubs.

[Teresa]

The dark spot on either side of the females, just above the anus, is called the gravid spot and does mean that babies are on the way.  It will get larger and larger until the babies are born.