I killed my cat...

I don't think it was the excel.

Your title is misleading! I thought you were talking about the cute fluffy kind

yeah, maybe I did that little play on words in the title on purpose a little...

but back to the point, The only thing that changed was the excel, a few hours after I added it (35ml initial dose for 34 gallons of water) the water was looking pretty cloudy. I just kind of ignored it and the next day added another 6ml before going to work. The next day (today) I did the same 6ml and when I got home there floated the cat.

There was one other bit of strange behavior from my sae's on the second and third days, they just continuously swam toward the filter outlet, and I mean continuously, like salmon swimming upstream to spawn. after the water change they have gone back to their normal more relaxed selves.

Sorry to hear about your Pictus. I'm not a big fan of OD'ing with the Excel, but perhaps there were a few other factors that played into the equation that weren't there before.
How old was the cat? If it was getting up in age, maybe he just wasn't as resistant to it as he was before.

I really haven't changed anything for weeks.

The fish was just over two years old and still growing well, he measured out at 5 1/2 inches when I took him out.

The day I dosed the Excel the water clouded, the fish started acting funny (swimming relentlessly toward filter outlet), and as I look over the plants my 2 week old spiral val that did have all kinds of new growth has melted.

After the water change all is clear, fish behaving normally, and fingers are crossed for the val recovering.

I really think it would be just a little too much of a coincidence that my fish died and the others acted up and my plant melted all within 2 days of dumping in way too much excel.

Maybe it was a combination of things. I O.D.'d excel 6 days straight at 3x and my Pictus and SAE's never seemed bothered.

Hmm, can excel 'expire'? Maybe you got a bad batch, or it was more concentrated for some reason?

Strange. Sorry to hear about the Pictus.

-Dave

Yeah thanks Dave, I really liked that fish, good personality and beautiful... oh well.

On a side note, the excel DID take care of my algae problem, everything turned reddish or white and fell off. So I guess the glass is still half full.