The guppy looked like it was pretty much on it's last breath, it was really struggling. At one point I thought it was dead until it started swimming again. I was just going to fish it out with a net before my wife got me away. I was away for a good hour, so it very well could have died...
I have a Pleco (very calm) in my tank, as well as another small catfish which the pet shop was calling a 'pegasus' (very darty). There were 2 guppies, 1 died. The second one seemed fine for a couple of days, and then I came home one day and it's fan was torn up, and it was really struggling...