A word of caution on goldfish. They are notorious for bringing in disease and parasites. During times of year when you fish are stressed as in early spring and during spawning, your fish could succumb to the new disease and parasites the goldfish brought in.

Many intensive aquacultures have considered using goldfish for forage but have declined for the above reasons.

Also, make sure it is legal to bring in carp and goldfish in your area as some states and provinces may have restrictions on them.

Carp can have nasty repercussions if they escape you pond and end up in a waterway that does not have the predators or species to keep them down. In Austraila they are having a hell of a problem due to introduced carp as the carp are destroying habitat and eliminating rare native species.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.