Corydoras breeding cycle?

[Ken Burke]

I was watching my red sailfins spawn this morning and a thought occurred - Why do my corydoras go through dry spells with virtually no spawning, then weekly spawns?  It feels like spawning cuts off in late fall, then picks up in the spring. I’ve had these guys for 2-3 years, and panda corydoras for even longer. Has anyone else noticed this?

 

[Fish Folk]

I’m just guessing…

Hygrometrics? Barometrics? Daylight extension?

My Xenotoca doadrioi were like your Corydoras.

I figured out how to “fool” my Mountain Redbelly Dace with light. I always keep them in low light until I want them to spawn. A week or two before spawning, I feed heavily and change water a bit more frequently. Then I add stone tray, and turn lights on full bright for 72 hrs. 90% success results. Here’s my latest haul of fry from that technique…

With Corydoras, we found that upping certain foods + increased flow + leaving on a night light all helped. But we didn’t breed enough to notice big seasonal differences.

Edited June 13, 2023 by Fish Folk

[Ken Burke]

Three reasonable hypotheses’  

hydrometrics - I’ve really backed off on my water changes over the last year. Water changes can (and do) prompt spawning, and I’m guessing water from the city could vary depending on the season.  But the only way this could impact breeding is with regular water changes, and I’ve been pushing the limit in my lack there of.  Not as likely. 
 

barometric - possible. I’ll need to track the barometric pressure to know. 
 

daylight extension - not as likely, though testable this fall.  My tank is in an interior room and gets very little sunlight, though you can see two windows from the tank. This fall I can have lights in the living room come on an hour or two earlier. 

[Mary W.]

I have noticed the same thing with my corys (trilineatus and pygmy).  Spawned a lot during the fall/winter, now nothing.  No change in light cycle (other than obviously the outside light cycle), temp, water change schedule, water parameters, or feeding.

[Guppysnail]

My panda, melini and Pygmy are the opposite. Winter is breeding fest. 
The reason i determined for mine was light schedule. In the summer I get a lot of natural sun through windows. It’s direct for short durations. Over the winter it’s very limited and nothing direct and bright. 
So over winter I leave my lights for my emergent gardens on 7am-7-8pm and the tanks get a full 8 of tank lights. 
Summer plant lights are 9-10am- 3-4pm and tank lights are only about 5-6 hours. 
So winter they get brighter longer light. Summer they get only small periods of intense light. 

[JimOp]

I find that for many cories it is a water condition thing. They like to spawn when the water is cooler, it is why water changes can sometimes cause them to spawn. I keep my community tank in soft water with the temp at 72 degrees. My cories spawn every 2 weeks or so. I don't try to raise the fry, but if they live they live kind of thing. I have 3 big females and 4 males. Due to how they mate, Cories need multiple males (at least 3) for a female so if you don't have enough males they may not spawn either. 

[nabokovfan87]

On 6/11/2023 at 10:45 AM, Ken Burke said:

Why do my corydoras go through dry spells with virtually no spawning, then weekly spawns?  It feels like spawning cuts off in late fall, then picks up in the spring. I’ve had these guys for 2-3 years, and panda corydoras for even longer. Has anyone else noticed this?

I think they absolutely can be seasonal!  It's nature doing it's thing honestly.  Some animals spawn when they know that "it's time" and they have this innate sense that there will be other events happening which will lead to success for their young.   My black corydoras spawns the exact same month (pretty much almost to the day) 1 year apart.  That's about as clear of an indication I can give you.  My pandas would spawn insane, got to about 30-35 fish and then they stopped spawning altogether for two years.  Once those fish got to @knee and @Minanora they had been spawning a month straight for me and continued to do so in their new homes.  I don't know why they stopped, but they seriously didn't show any behavior for years.  Out of nowhere it was a daily occurrence (right after the black corydoras spawned!)

The one thing I did have some success with was playing with GH/KH to get some indication of a spawn trigger.  I couldn't tell you what it is with certainty, but that's fine.  We do know water parameters can trigger them and that is very likely associated with rain or other natural phenomenon.  Seasonal times, etc.

[Cinnebuns]

I haven't noticed this at all. I have been breeding panda cories for about 2 years now. They spawn for me about 2-3 times a week all year round. The only time they stopped was when I spooked them out of it for about 2 months. I added 3 yoyo loaches. 1 ended up being aggressive. Even after I removed the yoyos the cories not only didn't spawn but they were completely inactive. I had an idea to jump start them back into action. I grabbed 4 of my young juveniles from my growout tank and added them to the colony. Sometimes the presence of young fish will make the adults go "oh, if it's safe for them then I can make some babies and it will be safe for my babies!"  It worked perfectly. Literally the next day they were out from hiding and active and the day after that they were spawning. 

Ofc conditioning and cold water changes also work, but if they need an extra push this may help. If you don't have panda cory fry or juveniles available you could try another species. I have heard that even the presence of the young of another species can help but I haven't experienced it myself. You could also try hormones although that's even more of a far chance in my head. It's possible though. Infact, when I added those juveniles, I also ended up transferring some water from the original tank. That tank also had guppies who were breeding. It's possible there was some hormones contributing as well. 

On 6/13/2023 at 11:18 AM, JimOp said:

I find that for many cories it is a water condition thing. They like to spawn when the water is cooler, it is why water changes can sometimes cause them to spawn. I keep my community tank in soft water with the temp at 72 degrees. My cories spawn every 2 weeks or so. I don't try to raise the fry, but if they live they live kind of thing. I have 3 big females and 4 males. Due to how they mate, Cories need multiple males (at least 3) for a female so if you don't have enough males they may not spawn either. 

If you have the improper ratio of males to females they will still spawn, you will just get a higher amount of infertile eggs because they guys will get tapped. I had the wrong ratio for some time and still got about 80 eggs. I would find that one day all but a couple would be fertile. The next day none would be fertile. 

Edited June 14, 2023 by Cinnebuns

[nabokovfan87]

On 6/13/2023 at 10:12 PM, Cinnebuns said:

I haven't noticed this at all. I have been breeding panda cories for about 2 years now. They spawn for me about 2-3 times a week all year round.

It's so funny how we can have nearly the same fish and such different behavior!  Setup matters, genes matter! 🙂

[Cinnebuns]

On 6/14/2023 at 12:21 AM, nabokovfan87 said:

It's so funny how we can have nearly the same fish and such different behavior!  Setup matters, genes matter! 🙂

That's why it's always helpful to get multiple sources of info in this hobby. There are too many variables that can change what ends up happening. 

[Andy's Fish Den]

I have kept and spawned several species of corydoras over my years, and each one is different. I have aeneus that spawn a few times a week with no triggers. Some will spawn only if there has been a weather front come through that cause a drop in barometric pressure, others will spawn if I do a water change using cooler water. Then, I have others that no matter what, I have not been able to get to spawn, and no matter what the season is. 

[Ken Burke]

Very interesting. Seems like the results are all over the place.  
 

sometimes seasonal in the spring summer, others in the fall winter

sometimes wc triggers a sawn, but not always 

sometime a low front will trigger, but not always. 

so here is my hypothesis- in the fall my interest migrates to deer hunting. Less attention to the tanks results in less spawning 

[nabokovfan87]

@Ken Burke have you seen Eric Bodrocks presentation?

[Cinnebuns]

On 6/14/2023 at 5:41 AM, Andy's Fish Den said:

I have kept and spawned several species of corydoras over my years, and each one is different. I have aeneus that spawn a few times a week with no triggers. Some will spawn only if there has been a weather front come through that cause a drop in barometric pressure, others will spawn if I do a water change using cooler water. Then, I have others that no matter what, I have not been able to get to spawn, and no matter what the season is. 

Have you ever tried concolors?  I have had a group since Feb and have yet to get them to spawn. 

On 6/14/2023 at 8:06 AM, Ken Burke said:

so here is my hypothesis- in the fall my interest migrates to deer hunting. Less attention to the tanks results in less spawning 

Very plausible. I know I have been trying to get some concolors to spawn. I realized that I haven't put in as much effort to triggering them as I did with my pandas initially. Sometimes we forget about that factor!

[Ken Burke]

On 6/14/2023 at 11:46 AM, nabokovfan87 said:

@Ken Burke have you seen Eric Bodrocks presentation?

Nope. 

[nabokovfan87]

On 6/14/2023 at 4:03 PM, Ken Burke said:

Nope. 

I would love to see an updated version, but he goes through a ton of species and how to trigger every single one.
 

 

[Andy's Fish Den]

On 6/14/2023 at 6:32 PM, Cinnebuns said:

Have you ever tried concolors?  I have had a group since Feb and have yet to get them to spawn. 

 

No I have not kept that species.