I am not sure the fish oil is a good idea until you get him stable. The more you change his diet the longer it will take to get a handle on the problem. I don't know who's idea it is/was to do the fish oil thing, but it sounds like a second step to me and not an initial step. I would really keep him on one high fiber diet and that is it. No treats, no nothing - no milk - nothing but water and w/d until you get him stable. Of course you are going to do what you think is best! Keep us posted!