Are My Fish Are Pregnant?

Beginner fish keeper here, got my first 100litre tank around 4 months ago and have gradually stocked it to have; 2 F dwarf gourami, 1 M swordtail+3 F swordtails, 8 Neon Tetra,2 F molly, M/F kribensis pair, 3 Cory and 3 Yoyo loaches.

Recently I have been noticing the sword females and the mollies to grow large, and having checked today one of the molly seem to have grown suddenly and looks ready to burst, along with one of the swords having a darkened gravid spot (cant tell on the other two as the area is black)
I didn't expect this, as recently having a dip in the water quality has caused some sickness and I gathered that would prevent any breeding.
They are fed once daily, and only enough for them to eat in one minute rather than the recommended more as I have noticed they will literally not stop eating no matter how much I put in, and that DOES cause them to get fat.

My query is, is it possible for the sword male to have impregnated the female molly? I know there's that thing where they can hold sperm for a duration of time but ive had them for about 2 months and wasn't sure if that applied for that much time.
And the two sword females I can tell if they are pregnant fluctuate in size every few weeks gradually getting larger then losing it quickly, and I'm not sure if that's weight changes or theyve birthed and it had been eaten by the other fish?

I can try get s for visual input if that's the best option but I just want to avoid handling, they're all very active and hate the net so the only way to get a decent is to close my hand around them against the side of the glass.

 

Welcome to Fishlore hope our members can help you today

 

Yes, swords and mollies are closely related and can interbreed. Platies too. They can store sperm for up to six months.

If you are seeing fat bellies that disappear quickly, the babies are becoming snacks before you see them. Some may survive if you plant the tank densely and add some floaters, but if I were you I would not try to deliberately rescue them or anything, as your tank is pretty heavily stocked as is. If you start playing hero now you will end up severely overstocked, experience water quality issues and probably contract the highly contagious and incurable MTS, which will overrun your house. It happened to me!

Unrelated but, are you sure your gouramis are female? Female DGs are super rare to come by and usually need to be special ordered. If they are colored they are male, the females are kinda grayish brownish tannish and do not show the blues, oranges and reds. If they are not truly both female, I would return or rehome one as they'll most likely kill each other when they're older.

 

Yes, swords and mollies are closely related and can interbreed. Platies too. They can store sperm for up to six months.

If you are seeing fat bellies that disappear quickly, the babies are becoming snacks before you see them. Some may survive if you plant the tank densely and add some floaters, but if I were you I would not try to deliberately rescue them or anything, as your tank is pretty heavily stocked as is. If you start playing hero now you will end up severely overstocked, experience water quality issues and probably contract the highly contagious and incurable MTS, which will overrun your house. It happened to me!

Unrelated but, are you sure your gouramis are female? Female DGs are super rare to come by and usually need to be special ordered. If they are colored they are male, the females are kinda grayish brownish tannish and do not show the blues, oranges and reds. If they are not truly both female, I would return or rehome one as they'll most likely kill each other when they're older.

Mollies and swords cannot interbreed they aren't related closely enough for that (platies and swords yes, most strains available are from doing that with platies and swords), female gouramis can have touches of color but they are mostly silver, not brown. I have had a female of each color type.

Beginner fish keeper here, got my first 100litre tank around 4 months ago and have gradually stocked it to have; 2 F dwarf gourami, 1 M swordtail+3 F swordtails, 8 Neon Tetra,2 F molly, M/F kribensis pair, 3 Cory and 3 Yoyo loaches.

Recently I have been noticing the sword females and the mollies to grow large, and having checked today one of the molly seem to have grown suddenly and looks ready to burst, along with one of the swords having a darkened gravid spot (cant tell on the other two as the area is black)
I didn't expect this, as recently having a dip in the water quality has caused some sickness and I gathered that would prevent any breeding.
They are fed once daily, and only enough for them to eat in one minute rather than the recommended more as I have noticed they will literally not stop eating no matter how much I put in, and that DOES cause them to get fat.

My query is, is it possible for the sword male to have impregnated the female molly? I know there's that thing where they can hold sperm for a duration of time but ive had them for about 2 months and wasn't sure if that applied for that much time.
And the two sword females I can tell if they are pregnant fluctuate in size every few weeks gradually getting larger then losing it quickly, and I'm not sure if that's weight changes or theyve birthed and it had been eaten by the other fish?

I can try get s for visual input if that's the best option but I just want to avoid handling, they're all very active and hate the net so the only way to get a decent is to close my hand around them against the side of the glass.

Your tank has every type of fry eating fish you could have gotten. The swords, mollies, gouramis, and kribs will all eat fry and sometimes stressed females will abort their fry (and still have sperm stored for the next round of fry). Where did you purchase your mollies from?
Female gourami are silver looking, they are not that drab but they do not have the intense color of the males. So if your DG have intense color they are male. (other indicators are extended anal and dorsal tips to a pointy edge, not as obvious on Dg compared to normal gourami).
If your mollies came from any pet store or chain they are likely pregnant, most stores have the same suppliers and the supplies don't separate the males and females of swords, platies, mollies, pretty much any livebearer except guppies are not separated when shipped (females and males are separated for shipping with guppies, females are still pregnant).

I would honestly not expect any surviving fry with all the fry eating fish you have in the tank, you would need a ton of cover for even a few survivors, swords actively hunt down fry, mollies will eat the ones they see, gourami will eat them, and kribs will hunt them.

Bottom line, male swords cannot impregnate female mollies. It is physically impossible for them to do so, not only by how the gonopodium is shaped but the ancestors of the fish as well.

 

I stand corrected! I was thinking of mollies and guppies, which is a thing. Though there are a few people on YouTube who claim to have crossbred them, I can't vouch for that.

I personally don't see an issue with your situation - when I kept platies it was pretty much only so they'd breed in the tank and provide food for my angels. Live food is the best food!