Cory floated to the top, then came to and is swimming now

Right after lights on today, I looked up at the tank and one of the Corys turned upside down and floated up to the top of the tank. He looked like he was mostly dead. I pulled him out and immediately put him in a quarantine tank, and he swam around for a while as if he were a little bit disoriented, and slowly came back to life. He's eating and seems to be foraging around with purpose now.

All other fish in the main tank are doing fine, and I tested all of my parameters: ammonia, nitrite, nitrate, pH, hardness, everything. I test regularly, so I had a feeling it wasn't that, but you never know, so I tested anyway.

Any idea what could've happened to him?

 

Cories are weird fish to be honest. I've seen one of mine sleep on its side and I thought he was dying. That was two weeks ago.

 

It happened right when the lights came on- I almost wondered if he went in to some kind of startled shock. He's acting completely normal now. Even ate the food I put in the QT. I'll keep watching him.

 

I have an albino that doesn't do S&#$ but sit in the corner. Than at night he's all over the map doing something upside down under the plastic foilage and ornimants I have in the tank.

 

The poor cory went to meet his maker today. He had zero signs of any parasite/infection/etc. Everybody else looks fine. All water tests are still in perfect range.

 

Aww. I'm sorry you lost your cory.

 

I'm so sorry. I don't know what to say. If your water params are perfect, then you did everything correctly. He/she might of been from a bad stock.

 

I am sorry for your loss. Another thing I think might of happen he might of swam into the glass to hard I had one do that and I thought he was died but after two days he pulled though but he still swims weird but he is eating fine he just swims in a z pattern now.