text: Heavy metals, such as mercury have been found, in trace amounts in shell fish and cold water fish, mostly in the North East, due to pollution from years past. Your question, some may think of a simple one requires a complex answer, but to keep it simple; eating large quantities of anything is "bad" therefor eating smaller amounts is better. Understanding your diet will become more and more important as you grow. Check the FDA website for more information. But most of all keep asking questions.