I also stay at Cyberjaya. Bought my guppy from Dengkil ( RM 1- 2 ringgit per pcs) and from Bangi RM 3.00 plus/pcs. Some died and some survive at the beginning and after one month the guppy seem ok. Healthy and kicking. Got 2 fry also. I changed half of the water every week without using the filter or what so ever.

I dont know what happen to your guppy, maybe you select the problem one or unhealthy stock. I only buy guppy when they are many in the shop, if only left a few, i bet they are not the chosen one.

my 2 cents.

AAK