I have had 4 cory cat deaths in the past 48 hours. One was a large green cory cat that was in rough shape at the pet shop. Two were Julii Cory Cats that were very small and looked to have some redish gills from the pet store.

However, the last one was a peppered Cory and it lost its whole tail. I didnt think I got it from the store in that bad of shape, but I also dont think anything in my tank was capable of that level of destruction.

One more peppered Cory Cat is alive, but has some signs of damage. Is this fin rot? Would fin rot be able to consume a whole tail in a few days? What do you think this is? You can also see top half of tail is eroded.

Any clues would help?

I did dose the whole tank with Melafix. I used a little less than the recommended dosing and my whole house smells of peppermint and tea leaves. Seems a bt extreme.