# Corydoras fry found in cannister filter, advice please



## rubadudbdub (1 May 2020)

Hi folks.  I found two corydoras juveniles while cleaning out my oase biomaster 250. I estimate they're just under 10mm long, the panda masks are fairly clear to see.

I've put them in a fairly decent volume tropica plant bag and floated them in the main tank.

My plan is to keep them in this and change the water regularly. Add some duckweed and couple of small cherry shrimp to clear any missed food.  Feed will be frozen cyclops and crushed soft artemia. 

Does this sound reasonable? I'd rather thyy were a little bigger before putting them in the main tank. 

FYI Water parameters are pH 7.5-8 gH 9 kH 4.  Im fairly sure they spawned after a cooler water change in early Feb as I found a single tiny fry in the pre filter a week or two after.


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## rubadudbdub (1 May 2020)

Looking in the bucket of sludge that's come out the filter there are some tiny little white worms and infusoria type things flicking about.  I'll try to see if I can syringe any of these in as presumably some of these have sustained the fry so far. 

All suggestions gratefully received.


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## Conort2 (1 May 2020)

I wouldn’t keep them in the bag, with no water flowing through it I can’t imagine there will be a great deal of oxygen. What other fish are in the tank? The fry are a pretty decent size.

cheers

Conor


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## castle (1 May 2020)

What other fish are in the tank, if it's just smaller fish, at 10mm I'd say they're tank safe and ready. BTW congrats, pandas are lovely lil fish.


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## rubadudbdub (1 May 2020)

Main tank mate concerns are the rummy noses and a single blood fin tetra.  I've seen the former tear a small cherry shrimp apart who decided to float down through the group.   There's also a corydoras pygmaeus with a stumpy tail who has received a nibble at some point from something.  He's bigger than the fry are.

Concensus seems against leaving in the bag then.  What about a floating breeding trap? The square one with thin slots in the side. I'm sure I have one if I can recall where I've put it. Again with regular flushes as water flow is poor within them.


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## rubadudbdub (1 May 2020)

Some other options, a 19l spec or a home 40 both long established and home to some shrimp and a female endler in each who fight when together. 

Water in the 40 is virtually identical to the tank  they're in, the spec has aqua soil and alder cones so pH is 7 KH 1-2.

Or should I stop over thinking it and release them into the tank as suggested


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## dw1305 (1 May 2020)

Hi all, 





rubadudbdub said:


> Or should I stop over thinking it and release them into the tank as suggested


I'm pretty sure they will be all right. You could release them after lights out if you are worried about the Tetras having a go at them before they are settled in on the substrate.





rubadudbdub said:


> 19l spec or a home 40 both long established and home to some shrimp and a female endler in each who fight when together


I think either of those would do as well. 

cheers Darrel


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## Conort2 (1 May 2020)

I’d Just let them go if that is their largest tank mates, they’re pretty good at hiding anyway. They look far too large to be eaten by a tetra. 

If you are really worried do what Daryl has said and release them with the lights off. However I wouldn’t be keeping them in that bag too long.


Cheers

Conor


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## dean (1 May 2020)

You can always use a floating breeding trap 

Cody’s don’t need a good flow at that size 

You could use a lemonade bottle and drill lots of small holes in the sides not the base  and if you cut it so there’s a long neck type part at the top you can heat it up and bend it over the top of the tank to create a hook so that it stays in place 


Sent from my iPhone using Tapatalk


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## rubadudbdub (1 May 2020)

Thanks for the advice guys. I have let them go in a smaller tank with less potential predators. Water chemistry virtually identical.  I took a long time acclimatising them just to be on the safe side. 

I'll let you know how it goes.

I'm wondering whether to leave the sponge off the cannister intake pipe now. I did it as I was getting fed up with sifting through buckets making sure i didn't throw cherry shrimp down the drain.  But the odd Cory would make it all worth while. I've never seen fry in the tank.


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## Conort2 (1 May 2020)

rubadudbdub said:


> Thanks for the advice guys. I have let them go in a smaller tank with less potential predators. Water chemistry virtually identical.  I took a long time acclimatising them just to be on the safe side.
> 
> I'll let you know how it goes.
> 
> I'm wondering whether to leave the sponge off the cannister intake pipe now. I did it as I was getting fed up with sifting through buckets making sure i didn't throw cherry shrimp down the drain.  But the odd Cory would make it all worth while. I've never seen fry in the tank.


Id keep an eye out in the corydoras aquarium, the youngsters are very good at hiding until they’re large enough to not be eaten.


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## rubadudbdub (6 May 2020)

Update.  The two young pandas are doing well.  Conort2 was absolutely right. I've found another, smaller fry in the pile of leaf litter the parents use to spawn in.  It occasionally ventures out then goes back.

The leaf litter is a pile of alder cones in various states from cones to stripped twigs. There are remains of almond leaves that the shrimp have eaten, and java fern rhizomes.  On top of this there's a tangle of java moss. Theres a fair amount of old plant matter/mulm and shrimp poo that's collected in the area.

The parents are spawning regularly in the evening.  Most of the eggs are deposited by the parents diving into the leaf litter, sending little clouds of mulm out. A second female is also spawning now, who occasionally uses java moss and crypt leaves to deposit eggs on. 

The females take around 10 mins from T position to depositing the egg.  I've only ever seen them lay one egg at a time. 

Eggs have hatched since being laid, but I've not seen any tiny fry.   The parents and cherries took a lot of interest in the leaf litter around hatching time, so I'm wondering if they're being eaten.


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## rubadudbdub (6 Jun 2020)

Update.  Its been a busy month.  The house had turned into a corydoras panda breeding production line.  The parents are still spawning regularly.   They've changed habits and are placing eggs more on the large crypt leaves now.

The fry rescued from the filter have grown rapidly and are now mini versions of the adults. They spend most of their time eating and surfing in the bubble stream from the airstone. 





I've been trying to raise the fry from the spawning in the tank and have experimented with various methods to see what works best/allows for easiest maintenance :

12l separate tank with sponge filter, water changed 1-2x daily taken from the main tank. 
Plastic penplax fish carrier algae magnetted to the glass, replaced by a Marina breeding trap with multiple small w/c per day. 
Ceramic filter media hidden amongst the leaf litter and at the back of the tank, to provide refuge for the fry. 

Eggs laid in early May were collected from the java moss and leaf litter and raised in the 12l tank with sponge filter. Survival was pretty good, all eggs hatched, only 2 fry didn't survive.  Yesterday I moved 15 ~3-4 week old fry into a 40l soil substrate tank with their older siblings rescued from the filter.   





The little plastic tank/breeding traps were OK for hatching eggs on their own,  but both hatch rate and fry survival were clearly worse.  So I've abandoned this and let the  resident 1-2 week old fry out into the leaf litter . I'm sure an air  pump would have helped, but I didn't have a spare. 

The ceramic rings trick is something I pinched off planet catfish, shared by a familiar face from ukaps.  I've got two fry who are now ~ 4 weeks old, happy swimming around the tank now.     




I've stopped collecting eggs for now.  I'm just seeing what survives in the main tank with the hiding places in the ceramic rings.  I've got ~ 20 little Corys and will run out of space for them if they all survive.  

I can see why people get hooked on corydoras.   The pygmae corydoras have been feasting on baby brine shrimp and microworms that I've been giving to the fry.  This week I've started seeing  the males displaying to females.   So now I'm sitting fingers crossed the pygmaes start spawning too.


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## Conort2 (7 Jun 2020)

rubadudbdub said:


> Update.  Its been a busy month.  The house had turned into a corydoras panda breeding production line.  The parents are still spawning regularly.   They've changed habits and are placing eggs more on the large crypt leaves now.
> 
> The fry rescued from the filter have grown rapidly and are now mini versions of the adults. They spend most of their time eating and surfing in the bubble stream from the airstone.
> 
> ...


Sounds like they’re very happy, must be doing a good job!

 Like you said you’re best off leaving them to it now, Corydoras fry will survive a lot of the time so you’ll end up with hundreds. Good thing is they’re pretty desirable fish unlike say a guppy so you should hopefully get some credit for them at your lfs or get a few quid each for them if you sell them privately.

cheers

Conor


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