Jay, Cheras Aquariums occasionally bring in good quality goldfish from China. Some of these fish are worth RM1200 each and are some of the biggest Ranchus I've seen!

Alternatively Arrowana aquariums (Jln Puchong, off Old Klang Rd) also occasionally have nice chinese/japanese goldfish.

Aquatics International (Subang), have a wide variety of goldfish. Usually local fish or imported from Hong Kong. Prices are reasonable.

Lotsa good goldfish places to go in KL/PJ area.