Hello, please can someone help. I purchased a molly fish to be company to my existing molly but by own research looks like I have 1 male and 1 female. The female was purchased after, im almost sure she's pregnant and researched loads but im still confused. We purchased the female beginning of July but how do I know when she become pregnant? Everything says 30-60 days pregnant but how do you know from when? She's a dalmatian one. I put her in a separate birthing box but after 48 hours felt bad and put her back in the tank. Im so unsure and want to care and do the right thing but how do I know when to do it or even be 100% sure shes pregnant? I'm sure she is as she has got a big belly and seems it's getting larger. I just Want to do the right thing. Can someone please help? Thank you in advance
Pregnant molly fish
- Thread starter Hlgrant
- Start date
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Andy Sager
Aquarium Advice Addict
Mollies, like the other livebearing fish ( Platies, Guppies, Swordtails), can hold sperm for later impregnation so you will never know when the fish got pregnant unless you know the first time the fish was in a tank with a male. So the " when" does not really matter. The best thing to do with a pregnant Molly is place her in a tank with lots of floating plants or fine leaved plants that the fry can hide in when they are born. Mollies can suspend the birthing of their fry until they feel secure that the fry have a chance of living so unless you have that type of set up that she is in already, she may not birth in the tank. If the tank is large enough, you can also place a divider in the main tank and keep the female on one side until she gives birth. Once she's had the fry, she can be placed back with the male. Once the fry are large enough to not get eaten by the other fish, the divider can either come out or the fry can be placed on the other side and when the female gets ready to birth again, she can be placed on the other side again. As for plant types, I've used live plants for this as well as plastic plants for this. I'm currently using floating plastic Anacharis for Gambusia which are notorious for eating their own fry. I am currently working with a 3rd generation of these fish so the plants must have helped as there are no other places for the fry to hide in this tank. 
Hope this helps.
Hope this helps.
Thank you for your reply its very helpful, we have a separate birthing box that we held her in but she seemed alone and not ready to give birth so I allowed her back I the tank. My tank is only 50l so we can't have a massive separate box. I just want to do the best I can. I've gone and brought new live and artificial plants today to help. I guess I'm just worried and won't to do everything I can to help her. I appreciate your help. Thank you
Andy Sager
Aquarium Advice Addict
Breeder boxes were the old way of getting fry but over time, it was found that the stress on the female being in the boxes made things worse, not better. Better to leave the fish in the tank with better cover for the fry.
Be aware that livebearing fish can really fill up a tank with fish so if you are going to continue letting the female have fry, she will overload your 50l tank rather quickly. If you have no plans on getting a larger tank, if it's an option, return the female and get a definite male. Males can live together without you needing to worry about being overrun with fry.
