I just did a water change, about 25%. I was looking around and noticed one of my Ps was missing. After looking around on the ground i figured the only other place he could be was in this cave thing that i have in the tank. I picked it up out of the water and out swam the pleco but no piranha. turns out he was stuck down in the other side of it, i heard him flapping around. I put the cave back down into the ater and he still didnt swim out after about five minutes. I then picked up the cave and turned it upside down. He came swimming out and was going nuts swimming all over the place going crazy. Now he is laying down on thebottom of the tank proped up next to a sword olant laying on his side just breathing. The other two Ps are swimming around like they usually would. I also changed the filter whenever i changed the water. Do you guys think that he is just really stressed right now or is something wrong?? Whats the deal??