I was away and my sister told me that one cory has been missing for two days. I thought that it died and that it may had been eaten by other fish but I found it stuck under some rocks. I noticed that the corydora was hanging on the top of the tank lately and I thought that it was suspicious. I don't know if the fish got sick because it got stuck or it got stuck because it was sick. Now that I released it, it looks stressed, not doing much and it looks a bit bloated, like it has a hump, kyphosis or something.