How do Corydoras not suffocate at night?

[i3k]

Being that they have a labyrinth organ and need to come up to the surface...I never see my panda corys active at night. They just go into their cave and stay there. How do they not suffocate overnight?

 

[Mark Hewitt]

I think they *can* come to the surface, they don't have to.
I have 2 x Peppered Cories and 1 x Pygmy Corry and I have *never* seen them at the surface!

 

[krap101]

I'm not sure, but I don't think cories use their little surface diving routine to breathe except in emergencies. I think it is to fill their stomach with air to swim better or something like that.

 

[BigJim]

I think they *can* come to the surface, they don't have to.

He nailed it. Cories have functioning gills. I don't know why cories like to breathe at the surface, but my pandas will suddenly burst from the bottom of the tank to the top for a breath and back down again. It's just cories being cories.

 

[Crepe]

My otos do the same thing. I don't know why either but it's fun to watch.

 

[Lowryder]

My cories do the same. They are crazy little buggers.

 

[HN1]

Being that they have a labyrinth organ and need to come up to the surface...I never see my panda corys active at night. They just go into their cave and stay there. How do they not suffocate overnight?

They do not have a labyrinth organ. They gulp air as an adaptation to low DO levels, but are gill breathers. Fish sleep.

 

[WhiteDevil]

HN1 is correct on most of it, fish do not sleep, they cant "sleep" they do rest but thats the extent of it. For sake of argument though we do call it "sleep" because our definition of sleep and rest are totally different. You need eyelids to sleep, you dont to rest.

Here is a scientist's answer to the sleep question
Do fish sleep?

 

[HN1]

Infinitely debatable even within scientific circles... Here's another scientist's opinion. Search past the top google return and you're likely to see many others.

"But fishes do have a period of reduced activity and metabolism which seems to perform the same restorative functions as nocturnal sleep does in humans. Some are more obvious about it than others and actually rest on the bottom or in coral crevices, and parrotfish secrete a mucus “sleeping bag” around themselves before they go to sleep. If you get up quietly in the middle of the night you will find your goldfish in an almost trance- like state, hovering near the bottom of the tank making just the minimum correcting motions with its fins to maintain its position in the water column. If you put food in when they’re like this they take noticeably longer than usual to respond, as if they have trouble waking up."

Everyone should read the definition of sleep and a few opinions and make up their own minds IMO.

 

[cwt]

my cories generally come to the surface after a period of active browsing for food... guess that means they were 'out of breath' at the time. Otherwise, they act just like every other fish.

 

[jestes]

Like it was said earlier, cories usually live in slower moving streams in the wild, and sometimes these streams have low oxygen levels. They can swallow air and basically use their digestive tract as a lung. My girlfriend has a big pleco that will do the same thing. He's about 15 years old, and he'll slowly swim to the surface and take a big gulp of air. You can literally hear it.