Thanks svang, yeah the white one I've had the longest, for about 5 or 6 months.
I feed them 3 types of hikari goldfish food: Lionhead, Oranda gold, and Saki-hikari fancy goldfish purple type (color enhancing).
I also give them de-shelled peas once a week to make sure they don't get float.
amazingly, this tank stays very clean with just a single Koralia 2 pointed at the bottom, probably because of the saki-hikari food.