For the last two weeks my ferret has had diarrhea every time he goes to the bathroom. I took him to the vet today and after testing a stool sample the vet said they couldn't find anything that could be causing this. The color is normal it just seems to be watery. Does anyone have experience with this? Any suggestions? I was planning on changing his food to see if that helps but he's been on the same food since I got him so I'm not sure that will help much. 

Any help/suggestions would be appreciated!