Breeding Cory

What should I do to help raise my Cory fry?

  • Replace the breeder box

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jameson_uk

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My Sterbai Cory regularly lay eggs and I thought I would have another go at hatching them.
I tried previously (https://www.ukaps.org/forum/threads/cory-eggs.56022/) but none of them made it.

Last week I took about 22 eggs out the tank and placed them in the Marina breeder box hanging on the outside of the tank.
MVIMG_20190627_062325.jpg


All but one egg hatched and all seemed to be growing but a couple of days ago I to remove about ten and I have had to pull out another few today.

I have tried a few different foods but they don't seem particularly interested and the first ten that died looked pretty thin. I had used LiquiFry No1 and I have also tried Hikarai First Bites (which I see other Cory breeders have used successfully).

Got me thinking of two thing that might not be right.
First off, the flow through the breeder box isn't huge and the temperature is probably a little erratic as it it outside the tank. As the water comes in at the top on one side and out at the top on the other side, I have a feeling that the fresh water is effectively just flowing along the top and back out again. I have been going daily 50% water changes (well taking out 50% and letting it fill back up with tank water).

Second was the food. The LiquiFry was only because that is only fry food LFS had but the First Bites seems to be used OK by some breeders.

I have lost a couple of Cory over the three years I have had them and would like to replace them so so you think I am better off looking at a different breeder box (The Ziss BL-2B looking quite interesting as it sits in the tank and has panels to allow water to flow though it, the 2B has a solid floor which I guess is needed for Cory rather than the 3B which has a mesh panel on the bottom allowing more flow) or do you think the breeder tank I have is fine and it is just the food that is the issue>
 

mort

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As they are hatching you can ignore my first advise which is to treat the eggs with methylene blue. This is the first thing I always did but I also kept them in a little jar until they hatched.
Your thought about the food being the problem would also be my first guess as to why you have no luck. When I first bred my adolfoi last I left the eggs in the tank with the adults but added lots of leaf litter and other botanicals. I knew I wouldn't have many survive but believe the ones that did did so because of the live food generated from the organic material breaking down. When I came to breed them proper I took the eggs out, hatched them and then added them to a grow out tank with large well developed leaf litter and ecosystem. I'm sure this got them going and I added paramecium (easy to culture yourself) then a mixture of banana and walter worms (again easy to culture) followed by newly hatched baby brine and micro worms. This seemed to get them feeding well and I could gradually transfer them to aquarium foods. There might not be a need to use these live foods as I have bred bronze cories and brought them up with crumbled flake before but I like to feed some of those live foods anyway.

As to your breeder box, I don't see why it wouldn't work. If you put the air stone below the inlet then you should get a small circular water motion going. Good luck.
 

jameson_uk

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As they are hatching you can ignore my first advise which is to treat the eggs with methylene blue. This is the first thing I always did but I also kept them in a little jar until they hatched.
I have use alder cones which I think achieve something similar.

As to your breeder box, I don't see why it wouldn't work. If you put the air stone below the inlet then you should get a small circular water motion going. Good luck.
The issue is when the airpump is cranked up the water is dumped in intervals and you can see it getting halfway down. It is also surprisingly long so not sure you are getting much flow at all in most of the container. I will try moving the airstone but not sure this will actually achieve much.

The misses has forbid me to start any worm cultures but I might have to sneak one in the cupboard....
 
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sparkyweasel

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I've used an old school floating breeding trap, so I don't think lack of flow is your problem.
A lot of newly-hatched fish will only take live foods, if it doesn't wriggle they don't recognise it as food.
Infusoria are your best first food, then micro-worms. I found that if you start with microworms some of the babies grow well and some fall behind. Maybe they were a little bit smaller when they hatched and couldn't manage the worms, or only the smallest worms.
You can get dried infusoria (eg Hobby Protogen) either to start a culture quicker, or to feed straight to your fry if you only have a few. They re-animate when you put them in water and either get eaten or start multiplying. I suggest getting some dried to keep ready, and starting a microworm culture, then you'll be ready for next time.
 

tam

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If you are worried about flow you could pick up a tiny pump - I've seen breeding boxes sold with them attached instead of the air uplift - have a look on ebay. I've run mine using a bit of airline syphoning from my HOB as the water level sits just above.
 

Polly

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I had baby Cories last year. C. paleatus. It wasn't intentional. They spawned and I saw some of the eggs on the moss in the tank. Decided to see if they'd hatch and put the moss in a 4 litre sweet jar, with tank water and an uplift tube filter - literally a piece of uplift tube with an airstone and uplift tube top (to keep it all together) and a piece of matured filter sponge in the bottom. I also threw in a small fistful of sand from one of my tanks. They hatched, and grew very quickly. Didn't lose any. At first they fed on what was in the moss, then they started rooting through the sand and at that point I started feeding them crumbled JBL granomix. 1 litre water change every day was probably a bit ott, but I was siphoning off any uneaten food anyway, they grew really well and were healthy - I didn't lose any. At just under 1cm I transferred them to the main tank and they thrived until I sold the lot as I wanted smaller Cories that wouldn't uproot everything when spawning.

20180508_185908-2124x1195.jpg
 

jameson_uk

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I've used an old school floating breeding trap, so I don't think lack of flow is your problem.
A lot of newly-hatched fish will only take live foods, if it doesn't wriggle they don't recognise it as food.
Infusoria are your best first food, then micro-worms. I found that if you start with microworms some of the babies grow well and some fall behind. Maybe they were a little bit smaller when they hatched and couldn't manage the worms, or only the smallest worms.
You can get dried infusoria (eg Hobby Protogen) either to start a culture quicker, or to feed straight to your fry if you only have a few. They re-animate when you put them in water and either get eaten or start multiplying. I suggest getting some dried to keep ready, and starting a microworm culture, then you'll be ready for next time.
I though that LiquiFry No1 was meant to be similar but I haven't actually looked...


If you are worried about flow you could pick up a tiny pump - I've seen breeding boxes sold with them attached instead of the air uplift - have a look on ebay. I've run mine using a bit of airline syphoning from my HOB as the water level sits just above.

How tiny? I have struggled to find pumps that are anything less than 150lph.
 

jameson_uk

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Ended up getting one of the Ziss breeder boxes. In the end, this had nothing to do with raising the fry but keeping me alive
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With the air pump on anything but minimal the noise of water being dumped into the breeder box was amazingly loud (search YouTube) but having it attached also meant I couldn't shut the lid shut so I was suffering from evaporation (which lead to more noise as the spray bar edged above the water). The fact I was also doing water changes meant the tank level was dropping even more (as you can see in pictures)

Since I have transferred the two remaining fry they seem far more active than they were in the external box. Whether this is a good or bad thing I can't tell. When I added food they did seem to react (which they never did in the outside box). Whether this might be down to signals given off by the other inhabitants I don't know (they all seemed to go crazy at the scent of it).

Sounds like I am going to have to look into getting a small worm culture going and keep it hidden it in the filter cupboard. Any advice of starting a culture (and keeping it going)
 

sparkyweasel

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LiquiFry No1 is tiny particles in suspension, better than nothing in an emergency, but no substitute for live. They claim it will encourage infusoria if its not eaten, bit I've found it goes mouldy and smelly, so I remove any that's not been eaten. It might feed infusoria if you put some in a separate jar while it went through the yucky stage, but a lettuce leaf is much cheaper. :)
Protogen (there may be others, Infusyl used to be one) contains actual protozoans in a dormant state, they become active soon after you put them in water. For a few fry it's easy to feed them direct. If you have a big batch it's cheaper to use a bit to start a culture and breed your own. Like a normal infusoria culture, but it gets off to a good start.

Microworms are easy; get a sandwich box and drill some airholes in the lid (the worms don't seem to try to escape),
mix some plain oats (supermarket cheap and cheerful brand) with boiling water to a thick paste, let it cool, put it in the box and put your starter culture on top. After a few days you'll see worms climbing up the sides of the box, above the goo, and you can wipe them off with a finger (or a bit of soft plastic if you're squeamish lol) and dip the finger in your breeder box. They live for a while in water, and your fry should go mad for them.
After about two weeks, start another box, seeded from the first, ready for when theoriginal goes manky; the porridge gets progressively more watery, and the production drops off. Clean it out and restart.
I haven't got any going at the moment, still getting things sorted out after moving house, otherwise I would send you a starter. They're quite cheap on E-bay etc.
hth
 

tam

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jameson_uk

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Will take a look as small pumo will always come in useful.

Fingers crossed for your two remaining :)
One
One thing I didn't think about with this internal box (and it is really obvious) is water changes. Being in the main tank I had to keep lowering it and then raising it. I think I managed to throw it around a bit as I was attending to hang it back on and one didn't make it. Not sure if this was the water change or stress of me throwing the box around...

The Cory are currently zipping all over and I suspect I will have a new batch of eggs very soon which I will try and do a better job of looking after
 

Polly

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The problem with breeder boxes is that being open to the flow from the tank, most of the food is whisked away before the babies get the benefit. They need to feed almost constantly to grow properly. This is why I used live moss, matured sand and plants. All of these harbour nitrifying bacteria and the live plants and moss use up ammonia. The moss also encourages tiny critters that the babies feed off :) Once the babes were active, I put in some Limnophila sessilis and a couple of pieces of Salvinia auriculata to ensure a healthy environment. These babies grew faster than any I've ever grown in bare tanks or a breeder box.
 

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