Well, it was day 5 of treating my guppy for his tail fin ailment. He was doing so much better, back to his old self. I even changed about 30% of the water last night. I had to go to town today, and when I left he was doing fine, swimming around the tank like nothing was wrong. Then when I came back home, he was missing. I knew that was a bad sign. So I started looking for him. I found him dead inside the cave.

I don't know what happen to him.

I did add some algae control liquid, "Algae Destroyer Advanced", I've used this product before and it didn't harm the fish. Could this be what killed my precious guppy? I didn't think about the algae destroyer reacting with the Melafix. I've changed 50% of the water to remove the algae destroyer. I did this for the 5 gal. tank also, just in case. I'll never use that stuff again.
But then, it still won't bring my guppy back.
