The dalmatian is kinda iffy...but it looks to be. Sometimes when you get them from the petshop chubby looking, it's because they ate too much. I've had that happen, gotten ones that looked about to burst only to have them poop for about two days. LOL Petshops way over-feed, they usually drop in those sinking things like vacation feeders and some fish will gorge themselves. If she stays plump for three days after you purchased her, you can bet she is pregnant. It's nigh impossible to buy adult female livebearers from pet shops who aren't pregnant, but it does happen maybe once out of ten times or so. lol It could be her first brood if she is and she'll only have around twenty-thirty or so, or she could not be very far along and will get bigger.
The gold dust, however, is very, very pregnant. I'm guessing it will be her second or third brood. For the first ones gold dusts rarely get very big, usually barely noticeable(that's the experience I've had with all of mine anyways, there are always exceptions of course!), and yours is huge. Expect at least 50-80+ babies from her, they tend to have pretty small ones in comparison to mollies like the larger lyretails and sailfins like your dalmatian. But be sure you have hiding for the babies or a great many will be eaten. I've seen mothers alone eat more than thirty babies. =(
Be sure to keep them in a nice quiet area and give them a whole lot of places to hide. he problem with buying pregnant females, which I used to do allll the time, is that the move and new tank is very stressful for them and sometimes they abort. So the more quiet you have in the area for the first week or two, and the more hiding places you have for them, the healthier they and their broods will be. =)
