Pretty little live fish, perfect for your tank or pond.
They eat all kinds of things keeping the water clean.
All kinds of things eat goldfish, they are an important link in the food chain wherever they are.
Most predatory species that eat live fish can also be weaned onto dead alternatives. Some of the species used as feeder fish (goldfish and rosy red minnows) contain high quantities of thiaminase, an enzyme that destroys thiamine (vitamin B1) and when fed in large quantities causes nutritional imbalances. Wikipedia