Bloated cory fry

[Ciciwarriner]

I have recently hatched Corydoras eggs for the first time. I have 3 fry currently in a breeding tank floating in the main tank. Two of them seem fine and are behaving as expected, but one of them seems to have a bloated abdomen and is struggling to swim or move around.
Can anyone tell me what this is? I thought maybe it was gas bubble disease but im not sure. I have a 180litre planted tank and j check the water quality at least once a week.
The swell seems to be getting bigger each day and now he can only lay on his side.
Added a photo of the other fry for comparison.

 

[CassCats]

Internal bacterial disease, unfortunately nothing you can do but hope he recovers on his own.

With cory fry, you need to add a layer of sand from the adult tank to the fry tank. It increases the chances of survival and prevents bacterial issues such as these. Bare bottom tanks/containers aren't great for cory fry who will be in constant contact with the bacterial layer on the surface.

 

[Ciciwarriner]

Internal bacterial disease, unfortunately nothing you can do but hope he recovers on his own.

With cory fry, you need to add a layer of sand from the adult tank to the fry tank. It increases the chances of survival and prevents bacterial issues such as these. Bare bottom tanks/containers aren't great for cory fry who will be in constant contact with the bacterial layer on the surface.

Ok thank you, unfortunately he passed overnight, in terms of protecting. The other fry, i read that gravel is too harsh for fry, i only have gravel in my main tank, is gravel ok or should i get some sand for them?

 

[CassCats]

Sorry to hear he's passed, unfortunately that is the case for this situation. Fry are delicate and when it comes to raising them, you will lose some.

Corydoras really need sand, so I'd definitely get sand for the baby enclosure and for the adults. It could even just be a small "beach" of sand for the adults, they just should have access to sand in order to sift it (it's a natural behavior for them.

 

[GaryE]

Also, you mentioned you check the water weekly. If you want to decrease problems don't check - change. I find my Corys do best if I change 30% or more of the water every single week, without fail.