Do you know your water parameters?
Ammonia
NitrIte
Nitrate
Do you know about the nitrification cycle?
If you need more information about that, and additional tips for aquarium keeping the article link in my signature will help.
As for the fish, I can't really see, though there is a darker spot in the pic, it seems it is possible.
The amount of time for them to carry the babies, is about 28 days.