Koi are a type of Goldfish, Goldfish are a type of Carp. Carp are a type of fish, and if you use a fly rod, it is still fly angling.

Fly Angling is not fishing for a certain type of fish (excluding all other fish), nor is it about catching fish. Fly Angling is the opportunity to practice the art of casting a fly line, over open water, trying to fool a fish into taking your fly!

~Parnelli