Why discus fish is expensive?

Most people who keep simple freshwater fishes after seeing discus fish for the first time think  “I want to have this fish” but this wish can be destroyed when seeing the price of discus.  If you buy really quality discus the price can reach 100$ - 200$ for a pair. So why are discuses so expensive?

Very important factor that affects discus fish price is keeping. Discus is not very easy fish to keep.  It is not like simple community tank fishes like guppy (Poecilia reticulata) or barbus (Cyprinidae family) which can live in a poor quality water. Discus needs good quality water which should be changed regularly. Of course you should always check water parameters such as pH, GH, KH, NH4/NH3, NO2, NO3. Keeping water quality is not so easy when there are so many parameters, sometimes it can be very complicated.

Another thing that makes discus expensive is breeding discus fish. Breeding discus is always a hard task because you have to make perfect conditions to feel him like in its habitat. Only then he can start breeding. Also you must know how to act when discus starts spawning. Knowledge and passion about to the discus fish are the factors which show that not many people can start breeding discus fish. And that factor helps to be discus price increased.
Moreover discus fish is expensive because of fish food which they eat. Feeding discus fish requires not so much of a knowledge but high quality food such as raw turkey or beef hearts or livers, glass worms or mosquito larvae which are expensive as well.

Of course we shouldn't forget that it is very important if discus fish is aquarium-bred or wild caught. By saying wild caught I mean that it can be caught in the wild or it is pure offspring of discuses which have been caught in the wild.
So here I listed the main factors which make discus expensive.  But I hope this wonderful fish is worth to be expensive because of its beauty and performance.