nil: The shop is called 繽紛, very big in flower street. The peat is from the brand "Schurtz" (or sth similar, can't quite remember the spelling). It is called Canadian sphagnum peat moss (just ignore the moss, check the ingredient, it should only contain sphagnum peat). It is a fairly big bag of ~7 litres for $54.
To make it sink (ie for keeping killifish), u need to boil it so that it is water logged. I "ting" them with water in the microwave. Or else, just put them in a fine hole nylon stocking and wrap them in filter wool and put into your filter. Btw, u might want to wash it first to remove the fine dust.
The water from the peat will give a slight tea color appearance (just like from the sink wood). The tea color can be filtered away using active carbon. But i find it acceptable so i can't be bother to keep the water in a separate container to filter out the tea color.
Actually the cost is even much lower for a bigger bag. They got one containing ~70 litre for $200 (and also ~110liter for $270). If one can get a few people to share, it is really very very cheap, say 10 persons, $20@ for ~7litre, compared to $54 for ~7liter pack. I just tried the small pack recently, very happy with the result. If anyone wanted to share for the big bag, count me in

. They are good for keeping killies!