Newly hatched baby cories!

[IndiaHawker]

Hi! Haven't been on here much lately as hopefully everything seems to have been going smoothly. If anyone remembers my previous posts my last mishap was my first batch of cory eggs being eaten, which was largely unpreventable at the time seeing as I had nothing to keep them separate, and by the time the breeder box and fry food had arrived the eggs were gone and I believe the bristlenose in particular was feeling exceptionally well-nourished! Anyway I've just carried on as I have been, hoping for some more eggs but not being too optimistic - the breeder box came with a removable partition to put a breeding pair in the top and the eggs would be released and go into the bottom section, but I took this out as don't like the idea of squashing a couple of adults into the tiny box

Anyway, a few days ago I woke up to a lovely large cluster of eggs (and a couple of tiny ones), once again on the glass. This time I was more prepared - very gently scraped them off the glass and into the breeder box with a box cutter blade and managed to get most of them in (I knew this was the only option as they would get eaten otherwise - in fact a few hours later I found another small patch of eggs and stupidly didn't transfer them immediately - were eaten up much more quickly than I anticipated).

Been monitoring them, most had turned that light brownish colour which I now know means they're the viable ones. Woke up today and they've hatched!! I believe there's still some more light brownish eggs that could hatch, but I've got a load of babies so far!

So now the next steps - am I correct in believing that I don't feed them for two days (so today and tomorrow) as they feed off their yolk sacs? I bought some powdered fry food but have no concept of how much to feed (the breeder box did come with some pipettes though?) - it says only as much as they can consume within three minutes but I have no concept of how much/fast these little ones can eat? Also I'm planning a water change today or tomorrow - the breeder box is suckered to the side but also says it's self-floating - so if I just unstick it during the water change will it just float at the top of the water? I'm having images of it tipping over and everyone escaping I've noticed a tiny amount of muck building up on the bottom of the breeder box unless I'm mistaken, but how on earth do I clean this out with the teeny babies in it?

Someone has offered me a free small tank with everything included except heater which I think would be a great idea for when they need a bit more space - however how long would it take to cycle it well enough? I got this current tank pre-cycled with fish included and kept a lot of the same water when moving it, so I'm still a bit new to cycling my own tank!

Help really appreciated, please and thanks!

 

[Byron]

I would put some dried leaves in, several. Fry always grow faster with leaves, as the leaves produce copious amounts of infusoria, the best food for all fry. I have raised cory fry solely from leaves, adding shrimp pellets once I could see the fry moving about.

Collect fallen (dead) leaves of trees like oak, maple, beech. Rinse them off, ignore any with bird droppings. Once waterlogged in the tank they will sink. You cannot have too many.

 

[IndiaHawker]

Wow great to know, thanks! Will try and collect some asap, and in fact have a bag of dried leaves laying around (completely separate raising-a-baby-hedgehog thing going on at the minute!) so will sort through them! Is the dried leaves thing something I should only do an in entirely separate tank or could it work within the breeder box? I assume that the dried leaves would make water changes even more crucial - how do I clean out the breeder box, or safely clean out any space with such tiny creatures in? The unhatched eggs are still in the tank and I believe that all that will hatch have hatched by now? But so wary about accidentally hurting them that I don't know how to safely remove them! Please and thanks

 

[Byron]

Wow great to know, thanks! Will try and collect some asap, and in fact have a bag of dried leaves laying around (completely separate raising-a-baby-hedgehog thing going on at the minute!) so will sort through them! Is the dried leaves thing something I should only do an in entirely separate tank or could it work within the breeder box? I assume that the dried leaves would make water changes even more crucial - how do I clean out the breeder box, or safely clean out any space with such tiny creatures in? The unhatched eggs are still in the tank and I believe that all that will hatch have hatched by now? But so wary about accidentally hurting them that I don't know how to safely remove them! Please and thanks

When I hatched a couple eggs in a breeding net (hanging in the corner of the main tank) I had 4 or 5 oak leaves. They waterlog and then sink down. This was a mesh net, not solid, so the water circulated through it. I removed it during water changes (lifted it out into a pail of the tank water). I would not want to be sucking any water out as the fry were invisible to me after the eggs disappeared.

I happened to see the pair spawn, and place two eggs near the thermometer, so it was easy to carefully remove them and put them in the breeding net on an oak leaf.

 

[IndiaHawker]

Really helpful, thanks! I've put off trying leaves until now as been unsure of how to do the water change and scared to disturb water as the holes in the breeder are only just small enough to keep the fry in - for example the other night I swirled the little lid around gently in the box to make sure the babies were alive, and the current pushed one through a hole to rapidly get eaten up as far as I could tell However otherwise it seems to keep them in.

I've had some deaths and I'm left with three babies. Upon realising I decided it was worth it to brave cleaning the box and it was easier than I expected. I'll accept that the deaths were likely error on my part as it's a first time thing for me and still involving a fair bit of trial, error, and guesswork. My likeliest guesses as to why this happened are 1) build-up of debris in breeder box possibly affected their water quality too much or caused them illness - was scared to clean it out in case I disturbed the water too much and any more babies came swirling out through the cracks. 2) Maybe they're not taking to the powdered food and starving? The three that are left did appear to be eating as far as I could tell tonight though - and trying out the leaves tomorrow. 3) Kind of following on from the last point, I figured it might be helpful to drop just the one shrimp pellet into the box in case they weren't eating the powdered food, just to see if they made anything of it. However they didn't appear to touch it and upon closer inspection it seemed to have developed a fuzz around it - I'm wondering if this could have been a really stupid thing I did that caused their deaths?

Anyway, my remaining three are now in a nicely cleaned breeder box, safe in the knowledge that I at least have figured out how to safely clean it now. This sounds really awful - but when I was transferring water back into the tank I purposely included the dead baby cories - I figured they looked pretty fresh and at least in their death could be a nice treat for my other fish. They were only millimetres long but I didn't know what to do with them, I don't think I'll ever have the heart to flush fish no matter how small and I couldn't put them in the garden as it's late at night here. I felt like it was a good thing to make use of their bodies in death if possible and not just chuck them away.

 

[Sarah73]

Ok! Welcome to the world of corydoras breeding! I have been breeding mine for years. Easiest way to keep them alive? Have another small tank ready and cycled for them, (sponge filter, leaves, and baby brine shrimp)! Mine LOVE baby brine shrimp and go crazy. There bellies are always fat. Great right? That's how you know they are eating. Also water changes are needed! Without these they will start to die off.

 

[Paul Steawrt]

I've been breeding corys for 2 years i'm no expert, but setup a normal tank. a 20 litre one from pets at home will do. always have extra sponge filters, you can never have too many. keep them cycled and pop them in when needed. the duo sponge filters you can swap the sponges. great for breeding tanks. put some sand in the bottom of the tank, and some moss. the best thing i use to feed my fry is grub pie repashy. just a small amount, not too much, it's a very dirty food. keep an eye on the ammonia levels or you will get a crash. white silica sand is best, to monitor the fry. once they are about 2 months old or big enough not to be eaten transfer them to the big tank.

 

[IndiaHawker]

Hi again, I'm back! As you can probably gather from the absence my remaining babies did unfortunately die - my best guess is that they didn't take to the food? I've read people saying that you can tell they're eating because they get excited and swim around when the food is put in - however I didn't witness this. I was using a powdered fry food I bought online that had good reviews.

However they've bred again, and hatched today! This time, I've put a sock over the breeder box I kept the eggs in, as I believe a fair few babies escaped through the slits. Unfortunately I still don't have a separate tank to keep them in, and just have no space until at least the Christmas holidays off work (nine working days and counting) when I actually have time to clear stuff out and rearrange possibly. I'm hoping (hoping being the operative word) that due to having only pretty small fish anyway that I'll be able to keep the babies in the breeder box within the tank until they're big enough to not be eaten. I currently have: 3 zebra danios, 1 red wagtail platy, 3 bronze cories, and a bristlenose pleco - do you think this would be do-able?

Also, feeding-wise - Going to try something different this time, going with Byron's suggestion and have collected some dead beech leaves (all I can find so far, no maple in UK) so will put some into the breeder box tomorrow once yolk sacs are absorbed. People have recommended baby brine shrimp, a few questions:

- Bought some frozen brine shrimp online a while back but says 'marine' on the packet - is this suitable for a tropical tank or not?
- Either way I imagine the regular brine shrimp are a lot bigger than the bbs therefore not suitable for my baby cories?
- If I'm feeding bbs, do they have to be live or can they be frozen?

Last thing - now I've got the sock over the breeder box I'm particularly worried about water flow being restricted through it. I do have an air pump with two bubble outputs so I could put one into the breeder box but don't know if it would help or hinder? The reason I'm reluctant to put them into a separate small container is because although I assume I could avoid using a filter if I do a daily water change, and I imagine the daylight in the room would be enough for baby cories as they like low light anyway, surely I'd have to set up some sort of heater as cold here at the minute? And don't have enough plugs/don't have another heater/would just be a lot trickier unless absolutely necessary.

Please and thanks for any help and advice!

 

[IndiaHawker]

 

[Byron]

I would add the dried leaves now; they will need time to sink, and produce infusoria. The tannins are also good for anti-bacterial issues too.

 

[IndiaHawker]

Thanks so much for the fast and knowledgeable response (as ever!). Leaves rinsed and in now - only put three in so far as such a small space and worried I'll affect the water a lot? But have more if necessary! Was wondering about that actually - do the fry nibble at the leaves themselves, or is it what leeches into the water from the leaves that the fry gain nutrients from? I have a small amount of knowledge on tannins, but don't think I've heard of infusoria before, know nothing about it!

Will I need to clean out the breeder box daily due to low water flow with the sock over it? Should I also pull off the sock and give it a good clean, or not necessary?

Please and thanks again!

 

[Byron]

Thanks so much for the fast and knowledgeable response (as ever!). Leaves rinsed and in now - only put three in so far as such a small space and worried I'll affect the water a lot? But have more if necessary! Was wondering about that actually - do the fry nibble at the leaves themselves, or is it what leeches into the water from the leaves that the fry gain nutrients from? I have a small amount of knowledge on tannins, but don't think I've heard of infusoria before, know nothing about it!

Will I need to clean out the breeder box daily due to low water flow with the sock over it? Should I also pull off the sock and give it a good clean, or not necessary?

Please and thanks again!

You're welcome.

For our purposes as aquarists, Infusoria is a collective term for minute aquatic creatures such as ciliates, euglenoids, protozoa, unicellular algae and small invertebrates that exist in freshwater [Wikipedia definition]. You can culture these in outdoor ponds and tubs, but they are readily produced from dried leaves which is probably the easiest; these critters feed on decaying organic matter, and nothing beats dried leaves for this while remaining clean [you would not want rotting fish or meat in the tank!].

All fry will eat infusoria, and studies have shown that aquarium fish fry develop faster when dried leaves are present. It may be the infusoria and the tannin/anti-bacterial aspect together. The leaves slowly decompose; I add a few more at periodic water changes as needed.

I have raised a number of Farlowella vitatta fry, which being vegetarian need algae and dried leaves were my alternative and the Farlowella readily take to these.

In an aquarium the leaves will not detrimentally impact water quality. The tannins might lower pH, depending upon the initial GH, KH and pH, but a few leaves will not do this to any degree that it could harm the fish.

 

[FishGuest5123]

Congrats on the world of fry. I had 64 goldfish eggs hatch last year and didn’t lose one! I put my eggs in a 10G tank with bare bottom. That way I could clean easier. They hatched right in the tank. I really encourage you to read up on making a baby brine shrimp hatchery and get some brine shrimp eggs. San Francisco Bay is a good brand and available on EBay or Amazon. All you need is a plastic water bottle, a desk lamp, a small air pump and airline tubing. Plus the eggs. It is really so simple and the best food for the fry. I fed Hikari First Bites 2 times a day and the shrimp once. They grew so well and were so healthy. Good luck and have fun! Oh, put a piece of panty hose around the intake valve of the filter so fry don’t get sucked in. Also, while the eggs are waiting to hatch, you can add a little methylene blue or malachite green to the water to prevent fungus on the eggs.

 

[Colin_T]

Baby brine shrimp are too big for newly hatched Corydoras fry. You should either prepare live foods well in advance of breeding fish (not easy to do with Corydoras that can breed any time but still worth exploring), or use egg yolk.

Hard boil an egg. Remove the shell and white bit. Push the yellow yolk through a handkerchief into a small container of dechlorinated water. Put a lid on the container and shake it up. Use an eye dropper to suck some of the liquid out and squirt it towards the fry. The fry will eat the smaller bits of egg yolk and it should keep some of them alive. After 1 week you can add newly hatched brineshrimp but continue feeding the egg yolk until you know all the fry are eating the new food.

Boil a new egg each day and make a new solution each day. Keep it in the fridge when not being used.

Feed the fry 3-5 times per day, maybe more if the tank has lots of filtration. If there is no filtration than change 50-75% of the water each day and replace it with water from the main tank.

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Rotting plant leaves in water produce bacteria, which in turn encourage infusoria (usually paramecium) to grow and eat the bacteria. Any non toxic plants leaves will work but they need to be in the water for at least 2 weeks (usually 4 weeks) before you get any infusoria. In a well filtered tank most of the bacteria and infusoria will be sucked into the filter.

If you fill the tank up with live plants you will get infusoria on the plants and there will be more food for the young.

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The following link has just about everything you need to know to start growing food for baby fish and is worth a read. It's pretty long so print it out and read it in bed when you want to fall asleep.
http://www.fishforums.net/threads/back-to-basics-when-breeding-fish.448304/

 

[FishGuest5123]

Baby brine shrimp are too big for newly hatched Corydoras fry. You should either prepare live foods well in advance of breeding fish (not easy to do with Corydoras that can breed any time but still worth exploring), or use egg yolk.

Hard boil an egg. Remove the shell and white bit. Push the yellow yolk through a handkerchief into a small container of dechlorinated water. Put a lid on the container and shake it up. Use an eye dropper to suck some of the liquid out and squirt it towards the fry. The fry will eat the smaller bits of egg yolk and it should keep some of them alive. After 1 week you can add newly hatched brineshrimp but continue feeding the egg yolk until you know all the fry are eating the new food.

Boil a new egg each day and make a new solution each day. Keep it in the fridge when not being used.

Feed the fry 3-5 times per day, maybe more if the tank has lots of filtration. If there is no filtration than change 50-75% of the water each day and replace it with water from the main tank.

-------------------------
Rotting plant leaves in water produce bacteria, which in turn encourage infusoria (usually paramecium) to grow and eat the bacteria. Any non toxic plants leaves will work but they need to be in the water for at least 2 weeks (usually 4 weeks) before you get any infusoria. In a well filtered tank most of the bacteria and infusoria will be sucked into the filter.

If you fill the tank up with live plants you will get infusoria on the plants and there will be more food for the young.

-------------------------
The following link has just about everything you need to know to start growing food for baby fish and is worth a read. It's pretty long so print it out and read it in bed when you want to fall asleep.
http://www.fishforums.net/threads/back-to-basics-when-breeding-fish.448304/

Wow, they must be tiny. You can barely see a newly hatched brine shrimp so I can’t imagine anything not be able to eat them. My goldie fry, guppy fry, and platy fry all eat them the first week. Are you sure Corydora’s are too small? I know nothing about them so I have to take your word on it but freshly hatched brine shrimp are super tiny. Can you also explain what you meant in reference to making live foods in advance? I had to hatch brine shrimp on a daily basis to feed. If I had started them earlier, then they would be too big. Thanks in advance.