I can't figure it out, because I woke up one morning and one of my goldfish died, and then a day later another fish started moving really slow (It liked to hover around in one spot very closet to the ground), and when I woke up that was dead, now I only have one goldfish left. Did I try and put too many fish in onee tank ( I guess this is a 1.5 or a 2g I'm not sure), or was it a disease in the water or was my water not purified enough?

