Can you use marine fish food for goldfish?

How can a fish be a"cold water tropical fish"? "Tropical fish" means the fish come from tropical waters and do not do well (In some cases die) if kept in water that is too cold for them. Goldfish are Coldwater fish and need their water around 50F to 65F. So no, they will not do well in water that is constantly between 70F and 80F where most Tropical fish need their water to be.