Hatching & Raising fry

All posts regarding the care and breeding of these catfishes from South America.

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Hatching & Raising fry

Post by Coryman »

This is a subject that comes up quite regularly so I thought I would write down a few basic pointers the subject.

1. Are the eggs fertile?
This can be determined with reasonable ease, a fertile egg is usually a very light tan in colour, whereas an infertile egg will very quickly show a white centre and will turn completely white within 12 hours of being laid.

2. How long before they hatch?
Depending on the species it can take between three and five days for eggs to hatch.

3. How do I hatch them?
There are several ways to consolidate a spawning, but it is spawnings in community aquaria that initiate the most requests for help. The easiest only requires a small shallow, 1.5 litre plastic container, something like a sandwich box is ideal, and an air stone. The container is three quarters filled with water and floated on the surface of the main aquarium, the eggs can be removed from the aquarium sides with the aid of a clean razor blade and put into the container, where eggs have been placed on plant leaves the leaves can be cut from the plant and placed into the container. The air stone ensures that the water is both fully oxygenated continually moving, which helps to prevent damaging particles from settling on and contaminating the eggs. At this stage one or two drops of a propriety anti fungal preparation added to the water in the container can also help to prevent fungal spores from attacking the eggs. If medication were used then I would recommend that 50% water changes be made to the container each day for the first three days. Use replacement water from the main aquarium, this will dilute the medication in the container, so that by the time the fry hatch the water will be the same as the main aquarium

4. How do I raise the fry?
There is no need to feed the new fry for the first two or three days, as during this time they will draw nourishment from their yolk sac. When the yolk sac has been used up the fry are then classed as free swimming and will be actively looking for food. There are several foods that can be offered to give the fry a good start, the first of these that I use is Micro-worm followed by newly hatched brine shrimp and then after two days I start to introduce pre-soaked powdered flake food alternating between the two live foods. Once a feeding program has started it is very important to maintain good water conditions and to this end I would recommend daily 50% water changes, or even better twice daily, taking the new water from the main aquarium. The fry can be raised comfortably in this way for about a month when they should be large enough to fend for them selves in the main tank, of course this will depend on the size of the spawning and the number of fry hatched. Larger numbers of fry would be better raised in their own tank where they will have more space.

If fry are to be raised on their own in grow out tanks, these do not need to be very deep. Personally I use tanks that are 8 inches (20 cm) deep, it is the surface area that is the determining factor when it comes to the number of fish that a tank can accommodate.

Also read my article on the subject.

Last edited by Coryman on Fri Aug 25, 2006 7:03 am, edited 1 time in total.
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Post by L260 »

Great tips Ian 8)

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Post by daddyo72 »

Very helpful, thank you.
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Post by JoseAngelBarro »

Thanks; very good tips


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Additional help would be appreciated

Post by Beersnob »


Can you also assist those of us who are in process of trying to spawn cories, what methods work best? Any suggestions of what to do before hand?



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Post by megladonsharky »

:?: my dwawfs eggs were white with a dark spot . then went creamy ... fertile ??
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Post by GoldenChild »

Thank you, that's answered most of the questions I came here for!
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Post by Houston »

I think this answered what I needed to know :) As I just found my first set of cory eggs in my community tank this morning :) Thanks...houston
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Post by Ryan S »

Very useful.

From doing some reading on the subject â?? after consuming the egg sac, fry will do well on micro worms then newly hatched brine shrimp.
But my question is - can anyone give me some advice about these foods â?? where do I get them from, and what processes are needed to maintain a sufficient supply?


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Post by rochdale_iron »

Hi all,
I would just like to add a note about how long cory eggs take to hatch if i may.
I purchased 4 c. Julii, which i suspect to be actually c. trilineatus. I have 1 male, and 3 females.
The eggs my corys have laid have taken between 3 and 10 days to hatch.
Also, floating a container in the main tank hasnt worked for me, with any fry that hatched dying within a few days. I now have my fry in a 2ltr icecream tub ( well cleaned out first ), with an airline, and no heater. My fry now seem to be growing on well.

I hope it was ok to post this here.

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Not Pulling Eggs???

Post by bakagin1 »

Read your post, great information!! I was wondering has anyone ever kept the eggs with the group with success if so how was this done?? Thanks Bob
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Re: Not Pulling Eggs???

Post by bettas4me »

bakagin1 wrote:Read your post, great information!! I was wondering has anyone ever kept the eggs with the group with success if so how was this done?? Thanks Bob
My experience has been that the eggs will start to disappear not long after the spawn has concluded and are usually completely gone within 24 hours. The only survivers I've had from leaving the eggs in the tank came from some eggs apparently stuck to plants that the parents missed while snacking.
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Re: Hatching & Raising fry

Post by thelivelylady »

Thanks for the great information. It was a great help. As of noon today I have 7 panda fry.
Thanks again.
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Re: Not Pulling Eggs???

Post by apistomaster »

bakagin1 wrote:Read your post, great information!! I was wondering has anyone ever kept the eggs with the group with success if so how was this done?? Thanks Bob
Hi Bob,
I usually breed most of my small species of the Dwarf Corydoras in permanent set ups and as long as no other predators are present and I have an abundance of Ceratophyllum growth, my population will increase over time. I use this approach for the fun of it. If I were trying to produce them in commercial numbers I would use a more classical approach. C. panda is one that lends itself to a natural method of propagation in a permanent set up. I would use a 20 Long and only about two trios. More than this number may cause fewer eggs to survive predation. Thick Ceratophllum or Najas growth will greatly improve your numbers of fry. Bottom cover of pottery shards or hollow ceramic bio media seems to increase larval survival.
Larger Corydoras, I'll use C. sterbai as an example, eat too many of their eggs and possibly their larvae for this natural method to be as worthwhile.
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Re: Hatching & Raising fry

Post by bevans »

Do people use sand in their fry tanks, or bare bottoms? I read an article a while back (I think it was here) about raising adolfoi fry and the author said that they didn't have any luck until they put a thin layer of sand on the bottom of the fry tank. Has anyone else done this? And if so, what did you use? I have play sand in my grown cory tanks, but my LFS says they can get me silt sand if I want it.

I have only spawned paleatus before and they did fine in bare-bottomed fry tanks. But I have a spawn ofduplicareus eggs now and want to make sure they get off to a good start.
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Re: Hatching & Raising fry

Post by apistomaster »

I used to go with all bare bottom aquariums but I have found that a very thin layer of sand, less than 1/4 inch that at least conceals the bare glass produces higher survival rates for all the catfish I raise compared the the bare tank results. Actually I find this to be true of Dwarf cichlids and discus. It may be that the bacterial film that forms on the glass are harmful. I think that a little sand helps to produce a more complex ecology as well as a surface that bottom fish like to pick through.
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Re: Hatching & Raising fry

Post by Bas Pels »

bevans wrote:Do people use sand in their fry tanks, or bare bottoms?
I don't have any bare bottomed tank. Most importantly, I think the mirroring bare bottom will produce high levels of stress - stress reduces all natural immunity and resistance against deseases. However, I don't use thin layers, I use thicker layers, at least 2 cm (aslmost an inch) in which I put plants.

The plants are nothing special, mainly Hygrophyla polysperma and Elodea densa, but they do grow, and have thus a biological function.
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Re: Hatching & Raising fry

Post by Lugh »

Hi all-- I'm new here.

I'm currently breeding 4 peppered cories. I took the eggs almost as soon as they were laid and put them in a small 1 liter plastic tank, which is floating in an unpopulated 10-gallon tank.

The 1-liter tank has a 1/2" layer of sand as a substrate and it's currently got seven catlets in it with about 2" of water. I change the water daily with water from the 10G aquarium and feed the catlets with frozen baby brine shrimp. The only problem is that the catlets don't eat all of the brine shrimp, and now I'm starting to notice small bits of fungus beginning to grow on the uneaten food. I've tried to get rid of the uneaten food, but it's so damned tiny that it's virtually impossible.

Do you have any suggestions for avoiding or eliminating fungus problems? I grabbed a bottle of Rid-Fungus by Kordon and treated the 10G aquarium with it, then used that tank's water in the breeding tank. Will that work? Suggestions are very much appreciated.
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Re: Hatching & Raising fry

Post by Nitro Cory »

thanks for the help, my peppered & green cory just had eggs ..
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Re: Hatching & Raising fry

Post by SumpNFishy »

I'm starting to try and breed cory cats. I've started with peppered since you said they are pretty easy in your article.

I setup a dedicated conditioning 20 gal tank and put 6 in there (I think the proper ratio of 4 males 2 females).

Feed them good and use cold water during water changes to temporarily drop the tank temp. So far they have responded by laying eggs every few days.

My question is what is the normal quantity of eggs they lay? My corys will lay a dozen or so scattered all over the tank at most. I see some pictures on the web of large groups of eggs, but maybe those aren't peppered corys. Also, will they continue to lay eggs as long as they get good food and the water changes with cool water?

I collect the eggs as they lay them and put them in a floating container in a 10 gal tank with a few drops of meth blue (I use this for hatching angelfish with good results). As they hatch (one or 2 at a time) I move the fry into the 10 gal grow out tank. I have a few now, the oldest a couple of weeks old. I feed the powdered fry fish food for now, and will give them BBS as they get bigger.

I'm used to raising large batches the same age with my angels so this is a little more difficult in that respect. :?

Thanks for any input

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