Hi. Thanks for your query. Noted the history and understood your concerns. Both the parts of your question is unrelated and the first part about fish oil making the butt bigger is not really studied, documented or known so sorry for this one. Second part about white discharge from rectum is usually due to mucus production due to proctocolitis or such problems. I would advise you the following in such a situation: Get the stool and blood tested. Colonoscopy and biopsy should be done if a course of metronidazole does not help cure the problem. Also identify the foods and beverages that instigate or enhance the problems and stop these altogether. Watch for the water source of any infection or infestation and get the water treated accordingly to avoid recurrence.. Wash hands with soap and water every time you use bathroom. Avoid outside foods and beverages.