Catfish Breeding

HI All I have been deliberately vague in my title because I have a weird question. I looked into my tank today and I saw a little guy with his egg sack still attached. I looked into one of the caves and I noticed a bunch more. So here is the question. I have 5 plecos in the tank 3 BN and 1 Blue phantom and 1 clown. I also have 4 panda cories. Who did the breeding. The 3 BN are young and small, maybe 1/3 of the size of the adults in my other tanks if that big. I know at least one is male because I can see the bristles that have started on his nose. The others have not developed anything. The Pandas are all breeding age. Easy right must be the Pandas, except the male BN is guarding the cave that the wigglers are in. I am so confused...

Another problem is that I accidentally did a larger than anticipated water change in the tank and the whole cave was out of the water and the top of the cave still had air in it today. will this hurt these new wigglers?

 

It's 100% the Bristlenose Plecos. Cories are absolutely microscopic when they hatch, and they don't tend to lay in caves, usually on plant leaves or glass.

Here's what freshly hatched Cories look like. The eggs are about the size of sesame seeds, to give you a sense of scale.

 

It's 100% the Bristlenose Plecos. Cories are absolutely microscopic when they hatch, and they don't tend to lay in caves, usually on plant leaves or glass.

Here's what freshly hatched Cories look like. The eggs are about the size of sesame seeds, to give you a sense of scale.
View attachment 676861

I have read that BN need to be at least a year old to breed and these are at most 8 months. The male just barely showed his bristles. He is perhaps 2.5 inches long. These fry are impossible to get a clear picture of but they are maybe a quarter the size of a full RCS so you must be right. I seem to have more wigglers from this batch than I did from the two adults in another tank...

 

So what do you do to convince your cories to spawn? I have read that you must remove the tank water and slowly fill it back up 10% at a time and I have also heard that they will spawn on their own. I have never seen cory eggs on my glass so I am not sure.

 

So what do you do to convince your cories to spawn? I have read that you must remove the tank water and slowly fill it back up 10% at a time and I have also heard that they will spawn on their own. I have never seen cory eggs on my glass so I am not sure.

Good question. I've hatched and raised fry and I still don't know what makes them tick! The general advice I hear is to feed them well with frozen and live foods, keep the tank parameters good, provide them with places to hide and spawn, and then when you notice the females looking particularly rotund, do a water change using slightly colder water, ideally when it's raining. I'm not even joking about that last part, they can sense barometric pressure.

 

So what do you do to convince your cories to spawn?

I over feed my cories 2 days in advance of rain (barometric pressure helps) and the day before rain I unplug my heater. I then wake up at about 1 am and do a 20% water change with water around 50-60 degrees Fahrenheit, leaving my heater unplugged and feed again right after adding the water. When I wake up, there’s eggs all over the glass and decorations. I can then plug my heater back in.
The only cories this doesn’t work for is northern long nose corydoras.
I feel I should also note that I have a 6 time turnover in all of my tanks, as corydoras love high flow to spawn in.
I feed Wardley shrimp pellets to all my corydoras along with ground up mysis shrimp.
Baby cories love eating algae wafers and bug bites bottom feeder formula.