This morning I spotted a single fry in the aquarium. I know the live bearer reputation when it comes to breeding (and storing sperm!) so I was expecting fry eventually (it’s why I’ve kept my stock levels low!)

I had assumed one (orange lyretail) was pregnant when she arrived a month ago, she had a slight belly, rather than a sleek smooth line (she wasn’t wide though) but she didn’t get any bigger and to be fair, she’s the same shape now.
The silver Molly appeared to develop what looked to be a gravid spot a fortnight ago but she didn’t “look” pregnant (I guess I thought I’d see a fat Molly doing the swimming version of waddling around, who would then show signs of impending birth but nothing at all)
The marbled Molly has the sleekest shape of all.

The photo is from 2nd September - they look no different. Any ideas who it might be?

Anyway, mystery parent aside…someone had babies! I assume the rest of the fry were munched, but this one fry seems to be determined to survive and is like lightning. How long will it remain at risk of being eaten? If I leave it, how likely is it to survive? I have a fair amount of plants (20+ in 168l) as well as rocks and wood that form lots of nooks and crannies

That said, I think the biggest risk is the filter intake. Would it be safe to zip tie the carbon bag (that came with the filter) over the top? Can’t think of anything else that would fit that I could get fast…

Also, the male swordtail is currently picking fights with everyone. He’s usually VERY passive. I assume this is either a reaction to any signals (if they exist) from a female giving birth or just aggression because of the recent…. feast. Is this normal?

Thought I’d add a photo of the little one… not much bigger than the fine gravel

How quick a process is birth? A second fry has appeared… and I’m wondering if one of the mollies is birthing throughout the day. The first fry is bolting for cover as soon as it sees movement. The second fry keeps swimming out in the open near the adults (which makes me think it’s a new addition!)

Also may have solved the parent ID…. I’m guessing a plain coloured Molly wouldn’t have mottled fry? (the mollies were kept by colour in separate sections at LFS so can’t imagine it’d be a different coloured male…) So much for my theory about the marbled Molly!

You may get the odd one surviving if it's good at keeping away from the adults, but usually they do end up being eaten. They're not safe until too big to fit in an adult's mouth. The birthing process can take up to 24 hours to complete so you're probably right that she was still giving birth when you saw the second one. It will be the babies making the swordtail behave how he is.

Would been nice to see at least one survivor, they’re just too cute. Though truthfully this is the best outcome. I don’t want to be overrun or worrying about rehoming males etc

It’s been absolute chaos ever since. The swordtail is chasing the mollies yet seems to be trying to flirt with the tetra (as first I thought it was aggression but he never chases, just follows like a puppy then starts dancing around) someone has taken a chunk of of his pectoral fin.

The mollies have been having brutal fights. Strangely, the marbled one is usually the dominant one but the orange (usually very passive!) launched a full blown assault on the marbled. It was like a cat fight minus the claws; a rapidly spinning ball of fury!

I’ve turned the light off in the tank and the room, all seems calm for now. I haven’t seen any fry today so I’m assuming the feast is over… until the next one. Hopefully peace will resume again in the meantime.

When does this hobby get relaxing??