How do I care for cory eggs?

Hi! So, I saved a bunch of eggs from my albino corydoras last weekend. I put them in a 2.5gal cycled tank with a sponge filter and expected a really low hatch rate, because last time I saved eggs only about a dozen hatched. My plan was to start them in the 2.5 and then put them back in my 10 gallon when they were big enough not to get in the filter, which is covered with coarse sponge. And then give them away when they reached at least 1/2”.

Well…a lot more hatched than I anticipated, and my last count was somewhere around 140+. Yay! But also, help!

LFS says they’ll take them all, but I need to get them to about 1/2” first.

I have a 29 gallon that I’m trying to cycle to put these guys in - seeded with media from the main tank, fed with fish food, crushed coral added to keep pH around 7-7.2, temp around 80F. Of course, it’s not instantly cycling, and it’s been almost a week, and the babies are super crowed in the 2.5.

My question is: what if I just literally put the entire 2.5 gallon tank with all its stuff into the 29 gallon? I figure water parameters are the same, and the bacterial colony in the 2.5 is clearly handling the bio load for now. So basically just increase the size of the system and let the colony grow with the fish?

My other option is to spread the fish out among a bunch of uncycled containers and pray that I keep up with water changes to prevent any ammonia build up. Would I need to add some ammonia-absorbing filter media like the one sold by Aquarium Co-op?

Any advice would be greatly appreciated! Thanks!

 

I think if you moved the 2.5 filter to the 29 along with the fry you would be ok provided that you also ran a filter capable of sufficiently filtering the 29, if that makes sense? You would be transferring the existing filter, along with the bulk of the bacteria to the new tank and the new filter would take over the load eventually when the need arises. You could then remove the 2.5 filter after a few weeks once the 29 filter has picked up a cycle capable of dealing with the bioload.

congratulations on the spawn by the way!

 

Cory's are one of the easiest fish to breed and raise. But most people don't try. Good for you!

 

You can do exactly like you said. If you want you can also add some live plants, especially if you can get a big bunch of Java moss which will help you stabilize the tank and provide a home and lots of critters to snack on for the fry.

 

Thanks everyone! I’ll give it a shot and hope they do okay.

 

Congratulations! They're SO tiny when they're born, but in a week or so you'll really see the cory profile coming to life - they grow fast!

When I had mine (a paltry 40-50), they didn't come to the top to feed, obviously. I used a turkey baster. I put the First Bites in a container with a little water, sucked it up, then put it at least halfway down in the tank and squirted it out. You really don't need much for awhile, and you don't have to start feeding them til Day 2 or 3, they're living on the egg sac right now. They were quite happy with that, and I fed them 4-5 times a day. After a week I started alternating that with baby brine shrimp fed the same way. As they grow, you can crush up any fish food you have into dust and use that, too.

 

Congratulations! They're SO tiny when they're born, but in a week or so you'll really see the cory profile coming to life - they grow fast!

When I had mine (a paltry 40-50), they didn't come to the top to feed, obviously. I used a turkey baster. I put the First Bites in a container with a little water, sucked it up, then put it at least halfway down in the tank and squirted it out. You really don't need much for awhile, and you don't have to start feeding them til Day 2 or 3, they're living on the egg sac right now. They were quite happy with that, and I fed them 4-5 times a day. After a week I started alternating that with baby brine shrimp fed the same way. As they grow, you can crush up any fish food you have into dust and use that, too.

It can actually be really simple with just some first bite powder in your palm, use a Qtip, dip it wet, get some on the wet Qtip and get it as far down to the bottom as possible and shake the Qtip.....just spread the powder. These little fry will find their food by themselves. They will forage all day. I just use Hikari first bite, then a week later include some crushed high quality flakes and maybe grounded up bug bites/vibra bite/shrimp pellets using a mortar/pestle (I love my marble mortar/pestle!)...get them to the bottom and let the fish graze all day. Soon you'll see big and strong fry. I have never used live or even frozen food for my fry when they are growing up and found that I don't need to. You can certainly feed that but I think the high end processed food has plenty of nutrition and balanced elements.

 

Congratulations on a very successful spawn.

When growing out any type of fry one of the main things you have to do to help them grow fast is feed several times a day and water changes, lots of water changes. Fry emit a growth hormone that can impede the growth of their siblings. That growth hormone has to be kept diluted with water changes.

With this many corys you may need to change half the water every other day to keep them growing quickly. When growing out my last spawn of pleco fry I was having to do it daily but it was a small tank with lots and lots of super red bristle nose pleco fry. If you move these little guys to your 29 gallon you can probably get away with every other day.

To answer your original question. Yes, move everything over to the 29 gallon. Slowly acclimate the fry to the fresh water. They can be easily shocked by drastic parameters changes at this age. You can acclimate them easily by doing several water changes in the tiny tank they are in right now over a period of a few hours. By doing so the parameters in the tiny tank and the 29 gallon filled with fresh water should be the same.

 

Update
Hi everyone! Thanks so much for your help with this unexpected adventure. Just wanted to give you all an update and ask for a little more advice for next time.

Final fry count topped out around 200. Of those, about 75 survived - one batch went to the LFS last weekend, and the second batch are going today. I had moved everyone to the 29 gallon with water parameters ammonia 0, nitrite 0, nitrate 5, pH 7.2, KH 3,TDS 230, temp 76F. Two sponge filters, so plenty of bubbles and surface agitation, and some activated carbon. Feeding Hikari First Bites 3-4 times a day, plus some freeze dried tubifex worms every other day. In the last 2 days, over 30 babies died. Water parameters remained stable, I don’t think there were massive temperature swings, and I don’t see any obvious signs of disease on any of the fish, except that a handful seem remarkably skinny - however, that doesn’t seem to correlate well with the ones that have died. I saw a couple of them dying two nights ago, and they just seemed to be gasping for breath, and then they die with their little mouths gaping open. Can anyone please help me figure out what I did wrong? I feel so terrible that so many died.

 

I am very sorry to hear you are losing fry. What is your water change schedule like? Without frequent water changes things we don't test for slowly build up.

 

I had been doing daily water changes and then switched to twice a week and then once a week, because all the tests were checking out. In the future, I guess I’ll stick to more frequent water changes when growing out fry.

 

I had been doing daily water changes and then switched to twice a week and then once a week, because all the tests were checking out. In the future, I guess I’ll stick to more frequent water changes when growing out fry.

Fry need their water kept very fresh. It seems the slightest glitch in parameters can affect them.