I started giving my 4 month old pup fish oil pills at breakfast two weeks ago like my breeder does with her dogs. This past week, my pup woke me up almost every night between 2 and 4 am to go outside and diarrhea. Other than the night time stomach issues, she acts normal during the day, eats all her food, and has normal stool. I asked the vet about it this morning, she didn't really have any ideas. They gave me some FortiFlora packets to promote good bacteria growth. The vet didn't think it was the fish oil pills and did not recommend to stop giving them because she got the pills for a whole week with no problems. I can't think of anything she would be getting into during the day that would upset her at night. She isn't really ever left unsupervised, and does not get any food/treats/snacks between breakfast and dinner. She gets dinner between 5 and 6 pm every night. I am feeding Eukanuba large breed puppy with nothing added except that one fish oil pill each morning. Does anyone have any ideas as to what could be causing the night time stomach aches? Thanks.