I have to confess, I really think "the bulge" needs to be investigated before we start arbitrarily start throwing meds at it. Perhaps it is a fatty liver syndrome, which can cause immediate death, especially after a robust fish goes through a period of stravation, sometimes a short period. Perhaps it is something totally benign. Assuming it is a malignant form, and starting medication for such seems a bit archaic and premature.
Tim, I wasnt trying to belittle. I just find that, too often, people overlook this issue. Some people have INSISTED to me that there is no way that a water treatment can treat internal issues. Ideally, is in the link you provide, you want the fish to actually consume the meds in order to treat a GI tract. However, this is much easier said than done. First and foremost, you need to know the weight of the fish. How many of us can say we know how much our fish weighs?! Secondly, you'll need to find a way for the medication to adhere, and not dissolute, in water. And thirdly, youll need to ensure the fish intended eats the medicated food. Again, easier said than done.
In my profession, I regularly used a wide gamut of medications, and cringe at their misuse, and prophylactic administration for causes unknown, so I am a bit sensitive to it.