Help! My cories spawned! What do I do??

[Gypsum]

The two black cory fry seem perkier, now that they have a 'scaped tank and their new rasbora friends. One of them is more grey than black, with some black lines around its eye, and I had an exciting thinking it might be a CW045, but images on PlanetCatfish suggest it's a throwback to a more standard aeneus cory.

Still have at least two C. habrosus fry in the 125L tank. The corys I've worked really hard at raising are doing as well as the ones where I've done absolutely nothing other than say, "Oh, look, a fry."

 

[Gypsum]

Finally managed to get okay-ish photos of the two fry which have suvived my incompetence. The little black one looks like the parents, while the grey one looks very different. Mom would be suspicious that Dad was getting around!

 

[AdoraBelle Dearheart]

Haven't updated this thread in a while. Cories spawned again about 3-4 weeks ago, I managed to collect the eggs really soon after they'd been laid, so I think that might help account for why it's the largest batch of eggs I've ever had hatch. This is their fourth spawn/batch of fry.

All was going really well, was going so well that I got a bit complacent, not expecting losses since there had only been one or two that had died in the early weeks. But relaxing and thinking they'd got into the safe zone was a mistake...

Yesterday, I made this post in another thread;

Just removed 21 dead cory fry from the breeder box
They'd all been doing so well, I'd got a bit relaxed about them thriving. Always a mistake. Have heard that these sudden mass die offs are commonly a bacteria infection. Pretty sure it's not food, since I've been feeding 3-4 times a day, on a mix of baby brine shrimp, live microworms, and crushed powdered bug bites. I had added some sand from the parent tank a while ago, but just added more.

There are still a lot that are alive, active, swimming and looking well, so I hope the die off is over. But we'll see. It's always a gut punch when you lose some, but this has been my largest spawn, and also largest die off. So pretty bummed out.

By noon today, I'd lost another 23 or so.

Thinking now that it's an emergency, likely a bacterial infection sweeping through, I'm moving them to another tank. Just caught roughly 95 remaining fry and they're currently acclimating to a different tank. I've cleaned and soaked the net and breeder box under tap water, hoping the chlorine will kill off any bacteria, then will set it up in the new tank and move them back into there. I prefer the breeder box while they're this small since the netting allows for water exchange with the main tank, reducing the worry about tiny water changes in small containers and fluctuating water conditions, and excess food tends to escape through the netting too.

Won't be bringing anything from the old tank besides the fry and a few cherry shrimp who help keep the baby breeder clean. Adding fresh almond leaves, alder cones, live plant and fine sand from this established tank (breeding pygmy tank) and not from the parent tank.
Will try to nab some photos of them in a minute.

 

[AdoraBelle Dearheart]

Got the fry acclimated and into their new set up, and managed to get a headcount. 90 precisely remaining. So I did have around 140 before the losses over the last two days. Largest cory spawn I've personally had, and largest losses too Fingers crossed the move halts whatever was taking them out.
I accidentally laddered the tights leg that I'd been using as a net cover on the breeder box, and they're still too tiny to use the netting that comes with it. So I've put them in a large critter keeper with an airstone instead.
Managed to snag some photos! @Naughts @Gypsum @Slaphppy7 @PheonixKingZ @Byron @Wills @Essjay

I love this shot! Cloudly because it's looking through glass and a plastic container, but this little dude is sitting on a cloud of microworms, lol

Completed final set up. Ultra fine sand from this established tank, almond leaf, water and plants from this tank, which has healthy pygmy cory fry and plenty of micro-critters that can also serve as food between feedings. Added a few more shrimp and fresh alder cones. All being well, in a week or two I can release any survivors into this tank to grow on.

Bonus shots of pygmy cories! In the second especially, you can see the size difference between one of the adults, and the younger ones.

 

[Gypsum]

Cool. I moved my Aspidoras spilotus into a tank with a Bolivian ram, cherry barbs, and C. adolphi because I was being inundated by fry. We had far more fish than tank space, and catching them to take them to the LFS was an epic. The ram and barbs keep the population in check.

My C. metae and C. habrosus breed regularly, but I never see the eggs.... Just the occasional fry. The survival rate is low enough that we aren't being completely overrun, although the population is slowly increasing.

 

[AdoraBelle Dearheart]

@DoubleDutch Hi! glad you're still here. have a look above at my cory fry! I've lost a lot of the last two days which has me really worried. Have 90 left right now though. Any tips/thoughts/advice so welcome!

 

[AdoraBelle Dearheart]

Have lost one more cory fry since moving them at lunchtime. Watching them eating now, you'd never guess that there's anything wrong. Some are larger than others, as usually happens, but all look active, hungry and healthy. While I'm not religious, I'm praying to any god that might be listening that I don't have to remove another two dozen tiny corpses in the morning.

 

[AdoraBelle Dearheart]

Well, I guess the prayer worked, since there were ZERO tiny corpses in there this morning! Nor by noon
The kritter keeper water is brown with tannins from the almond leaf and alder cones, so hopefully that's helping.

I have seen the odd fry flicking though - bacterial? Not sure, and not sure what, if anything, to do about it. At least the deaths seem to have halted for now *touch wood* so I'm really glad I moved them when I did.

 

[PheonixKingZ]

Congrats! No clue what to do with Cory fry, but they are adorable!

 

[AdoraBelle Dearheart]

Still no more losses! Super glad I moved them when I did. Impossible to tell what was causing the losses, I tested the water in the previous tank, and it was fine. Perhaps the established sand in that tank was holding some sort of bacteria that was growing in their container? Any thoughts, @Colin_T ?

On the other hand, once I moved them I used sand from a different established tank that has plenty of pygmy cory fry in it, meant they got a 100% water change after acclimating, and I'd added a large almond leaf and a dozen alder cones, which are said to have anti-bacterial and anti-fungal properties. So any of those variables could be what helped. Kinda wishing I'd moved them after the first day of losses, but you live and learn. Very happy that the losses have *touch wood* stopped for now, with 89 fry remaining!

 

[AdoraBelle Dearheart]

Dang, lost one more cory fry, down to 88 now. They are different sizes, so perhaps just one that wasn't developing properly, but can't help getting nervous after such big losses so recently. Fingers crossed it's not the beginning of another mass die off. Others still look active, swimming around, eating their meals, so hopefully they're okay.

 

[itiwhetu]

If a had those fry in my fish room I would have them in a 36x15x12 tank and let them run, the more water you can give them the better. That tank is just 12 deep (I never know which way to write those measurements)

 

[Colin_T]

What's wrong with the fry?
How old are they?
What are they being fed and how often do they get fed?
How often do you do water changes and how much do you change?
Is the tank filtered?
What are the tank dimensions (length x width x height)?
What is the water temperature?

 

[AdoraBelle Dearheart]

I've just stumbled across this video about spawning and raising sterbai cories, but the info about how to raise them etc is the same regardless of species. But it truly is the clearest, most comprehensive explanation about how and why to do certain things to improve survival rates, and I picked up some tips too. Will add it to the pinned thread as well, but since we just talked about this and you're raising eggs/fry now, thought you might find it helpful too! Also happens to have incredibly clear, gorgeous macro shots of tiny fry - you can even see one moving in the egg. It's great!

 

[AdoraBelle Dearheart]

Have picked up this breeder box as recommended by the breeder in the video above::
https://www.amazon.co.uk/dp/B005QRDCP2/?tag=

So will try this out next time cories spawn, or if I deliberately try to spawn my sterbai's, which I'm thinking of trying once this latest batch of bronzes have grown out and been rehomed.