 #00 Bacteria Bloom (cloudy water) will occur 0 to 0 days after fish are added to the tank. The cloudiness, caused by initial bacteria growth, is not harmful to tank inhabitants, and will clear on its own. Have patience! I do have a question, you said you had a betta fish in there, when he was in there do you think you maybe overfed him? Have you vacuumed out the gravel? When the Betta died did you take the tank down and clean everything? Click to expand... 