Help! Sterbai Cory eggs aren’t surviving

[ashaquabarn]

I have a breeding pair of sterbai corydoras who are faithfully breeding weekly. I have been collecting the eggs because if not, the majority of them get eaten. I have left some in the tank to see if they survive and they all usually end up with fungus over them. The ones I have been removing which is between 20-30 each time, I move into a fluval breeding box off their aquarium and I have only had 4 actually hatch. They sadly did not end up surviving because they swam into the divider and get stuck 😞 I have Java moss, and almond leaves in the aquarium, keeping the nitrates at little to nothing and the temp is around 78… Why are the eggs all dying? I have even tried dipping them in methylene blue, but it doesn’t seem to work. Does anyone know what could be going wrong?? Please help! 

[DiscusLover]

On 3/7/2023 at 7:48 PM, aquabarn said:

I have a breeding pair of sterbai corydoras who are faithfully breeding weekly. I have been collecting the eggs because if not, the majority of them get eaten. I have left some in the tank to see if they survive and they all usually end up with fungus over them. The ones I have been removing which is between 20-30 each time, I move into a fluval breeding box off their aquarium and I have only had 4 actually hatch. They sadly did not end up surviving because they swam into the divider and get stuck 😞 I have Java moss, and almond leaves in the aquarium, keeping the nitrates at little to nothing and the temp is around 78… Why are the eggs all dying? I have even tried dipping them in methylene blue, but it doesn’t seem to work. Does anyone know what could be going wrong?? Please help! 

What are your water parameters? A key reason could be that there is too much hardness in the water for the eggs to hatch

[Lennie]

@nabokovfan87 may help!

[nabokovfan87]

Can you show us your breeding box / egg hatching setup? Are the eggs hatching in the tank itself with the rest of the fish?

If they are staying in the tank, please go ahead and show up the full tank.

Full water parameters including temp helps a little as well.

[AquariumCentral]

methylene blue  may help

[ashaquabarn]

The water we have here is very hard. I put some almond leaves in to help, but I clearly need to add more. I didn’t realize the ph was so high either. I have attached photos of the tank setup and breeding box, also. Can I use methylene blue in the breeder box? It filters water into the tank and I read that it’s not safe for fish to be in. So I did attempt a dip in it, but I didn’t add it to the breeder box itself. 

[AquariumCentral]

It won't hurt your fish, it's an antifungal/bacterial, so it's technically a unneeded medication. I don't have a real answer for that but here is a trustable article.

https://www.macsenlab.com/blog/methylene-blues-uses-in-fish-aquaculture/#:~:text=Methylene Blue is often used,eggs to avoid fungal overgrowth.&text=Methylene Blue is utilized in,eggs to prevent fungal overgrowth.

[DiscusLover]

On 3/8/2023 at 6:07 PM, aquabarn said:

The water we have here is very hard. I put some almond leaves in to help, but I clearly need to add more. I didn’t realize the ph was so high either. I have attached photos of the tank setup and breeding box, also. Can I use methylene blue in the breeder box? It filters water into the tank and I read that it’s not safe for fish to be in. So I did attempt a dip in it, but I didn’t add it to the breeder box itself. 

Ah thats the issue, your water hardness. Ph is not an issue at all, I have seen people hatch and raise cory fry in ph of 7.8. You might have to use distilled water or an rodi unit to make the water soft to hatch the eggs. 

[ashaquabarn]

On 3/8/2023 at 9:12 PM, DiscusLover said:

Ah thats the issue, your water hardness. Ph is not an issue at all, I have seen people hatch and raise cory fry in ph of 7.8. You might have to use distilled water or an rodi unit to make the water soft to hatch the eggs. 

Makes sense! Thanks!!! I knew they liked softer water, but I didn’t realize it was important for hatching. I’ll give that a go

[nabokovfan87]

On 3/8/2023 at 6:07 PM, aquabarn said:

Are these ACO test strips or which brand?  Need to see the scale.

[ashaquabarn]

On 3/8/2023 at 10:00 PM, nabokovfan87 said:

Are these ACO test strips or which brand?  Need to see the scale.

Sorry, I meant to put that in as well. Here it is

[nabokovfan87]

Is this the same testing parameters you get from your tap?  Water softener in the house?

Edited March 9, 2023 by nabokovfan87

[ashaquabarn]

On 3/8/2023 at 10:22 PM, nabokovfan87 said:

Is this the same testing parameters you get from your tap?  Water softener in the house?

We don’t have any water softener. I had a rock in there that could have been adding additional hardness so I removed the rock and added more almond leaves alongside a water change. 
 

here’s a photo of a test strip from water straight from the tap.

[Cinnebuns]

Is it just the 2 cories?  If so that is why you get a lot of eggs getting fungus. They are infertile. Cories breed best in a reverse trio of 2 males to every female. This is because female will lay enough eggs to tap the males of their sperm. What is likely happening is that the fertile ones are being eaten or otherwise not making it, which is another problem to address, and the others are no fertile because the male cannot keep up. 

First thing I would do is add more sterbai cory to get at least 6 total but more is better if the tank size allows. Try your best to get more males than female. 

I agree the hard water is not the issue. I wouldn't change that at all. If they are already spawning in the water then you risk making it worse by changing the water. 

Methylene blue is an option to prevent fungus spreading but it will not help infertile eggs. It will however save the eggs that are fertile from getting fungus from the infertile eggs. Given you are already doing a breeder box hatching, i kinda advise against using it. There are other things you can do utilizing the method you have already been doing. 

When I first started breeding my panda cories my first method was what you are doing. Make sure you have a turkey baster. When you place the eggs in the box, try to keep them seperated as best you can. If they are still sticky, stick as many as you can to the walls to utilize space around the box. Daily, or ever 2x a day, check the eggs. Use the turkey baster to remove any that become fuzzy. If any turn white instead of beige, watch them closely. They are most likely, although in my experience not alway, the infertile ones. They are the ones likely to develop fungus. 

This is a tank, not a box, but this is how I stick the eggs to the side to try to spread them apart. Sorry it was hard to get a good pic but I hope you can see the eggs stuck to the sides and spread out. Some are twins and are 2 right next to each other. I probably should seperate those as well but I've gotten lazy. 

If you happen to have neocaridina shrimp you can make this much easier on yourself even. The entire process can be done by just putting some shrimp in the box. They will "nanny" the eggs for you. They clean fungus off of fertile eggs. They will also eat infertile eggs which leaving the fertile ones to hatch. After I switched to using neos my hatching rates sky rocketed!!

If you have any questions at all feel free!  I will also link 2 thread I started with tons of info about some methods I have done for breeding cories. There are also other methods out there that are 100% viable. This is just a few i have done successfully. 

 

 

 

Edited March 9, 2023 by Cinnebuns

[ashaquabarn]

On 3/9/2023 at 4:57 PM, Cinnebuns said:

Is it just the 2 cories?  If so that is why you get a lot of eggs getting fungus. They are infertile. Cories breed best in a reverse trio of 2 males to every female. This is because female will lay enough eggs to tap the males of their sperm. What is likely happening is that the fertile ones are being eaten or otherwise not making it, which is another problem to address, and the others are no fertile because the male cannot keep up. 

First thing I would do is add more sterbai cory to get at least 6 total but more is better if the tank size allows. Try your best to get more males than female. 

I agree the hard water is not the issue. I wouldn't change that at all. If they are already spawning in the water then you risk making it worse by changing the water. 

Methylene blue is an option to prevent fungus spreading but it will not help infertile eggs. It will however save the eggs that are fertile from getting fungus from the infertile eggs. Given you are already doing a breeder box hatching, i kinda advise against using it. There are other things you can do utilizing the method you have already been doing. 

When I first started breeding my panda cories my first method was what you are doing. Make sure you have a turkey baster. When you place the eggs in the box, try to keep them seperated as best you can. If they are still sticky, stick as many as you can to the walls to utilize space around the box. Daily, or ever 2x a day, check the eggs. Use the turkey baster to remove any that become fuzzy. If any turn white instead of beige, watch them closely. They are most likely, although in my experience not alway, the infertile ones. They are the ones likely to develop fungus. 

This is a tank, not a box, but this is how I stick the eggs to the side to try to spread them apart. Sorry it was hard to get a good pic but I hope you can see the eggs stuck to the sides and spread out. Some are twins and are 2 right next to each other. I probably should seperate those as well but I've gotten lazy. 

If you happen to have neocaridina shrimp you can make this much easier on yourself even. The entire process can be done by just putting some shrimp in the box. They will "nanny" the eggs for you. They clean fungus off of fertile eggs. They will also eat infertile eggs which leaving the fertile ones to hatch. After I switched to using neos my hatching rates sky rocketed!!

If you have any questions at all feel free!  I will also link 2 thread I started with tons of info about some methods I have done for breeding cories. There are also other methods out there that are 100% viable. This is just a few i have done successfully. 

 

 

 

That makes a lot of sense! I had actually been wondering if a lot of them were fertile because when I was pulling them I noticed a lot seemed very white rather than transparent. I thought maybe it was because they were newer parents, not realizing there needed to be more males. I know they like to school but before I knew enough about cories I had gotten these two and several peppered ones and the peppered ones all died off. I’ll try getting some more sterbais then! Thank you! That’s super helpful! 
 

I was leery about using methylene blue anyways, so I would prefer to use the almond leaves or a more natural way like you mentioned. 

[ashaquabarn]

Could this fertilizer have anything to with why the eggs aren’t surviving? Since the eggs are in a breeding box using the same water as the tank, some of this is getting into their breeder box.

Edited March 13, 2023 by ashaquabarn

[nabokovfan87]

On 3/13/2023 at 8:20 AM, ashaquabarn said:

Could this fertilizer have anything to with why the eggs aren’t surviving? Since the eggs are in a breeding box using the same water as the tank, some of this is getting into their breeder box.

If you are having a lot of algae it could be excess nutrients. Most of the time it's not going to cause an issue.

Similar to easy green in some use cases and we all use that with eggs as well as other ferts.

[ashaquabarn]

I’ve had no luck with the last batch. I tried sticking a lot of eggs to the wall of the breeder box, doing a methylene blue dip, and spreading all the eggs further apart and removing ones that got fungus immediately. None of them survived that round.
 

They spawned again today. Can anyone tell if the majority of these are fertile or not??

[nabokovfan87]

Almost all of them look fertile to me.  This is the only one I see that isn't.

[ashaquabarn]

Thanks!! I was thinking a lot of them looked fertile too, but wanted to verify. I softened the water a little and removed components making the water more hard. I’m trying a separate container with meth blue and an air stone for this round.