Well i did say that was like 15+ years ago im sure that it wasnt considered bad then and sciences change as studies are done. i used to feed all my fish that we had gold fish and never had problems with them living to be about 5 or 6 years old. (Trigger, lions, a shark and even groupers) we (my dad brother and i) used to feel that they would eat live food in the wild so they should eat live food in the tank although gold fish dont exist in the environment that those fish came from they were the most available and inexpensive food source that was considered acceptable back then although guppies would be better if you were breeding them your self and letting the fish have at them (+1 for not feeding gold fish to saltwater fish)