Cloudy fish tank.

[Moonhead]

This morning we woke up to find our <BR>fishtank water had gone quite�cloudy. <BR>It was crystal clear the night before, <BR>and we only cleaned it out last Saturday.<BR>We've done some water tests for ammonia<BR>/nitrates and PH and all are absolutely <BR>fine.<BR>The fish (cold water) aren't surface <BR>hanging or showing any other symptom of <BR>illness at all.<BR>Any ideas on what could have caused this?<BR>I know the air stone for the pump needs <BR>replacing really as I noticed it's going <BR>a little crumbley when I cleaned the tank <BR>on Saturday, so would this be enough to<BR>cloud the water over night?? And if so<BR>is it harmful to the fish? I really don't<BR>want to get home tonight to find them all dead!

[morg_monster]

Hm I've kept goldfish for nearly 10 years in small but filtered / aerated tanks and this has never happened to me!  I would guess if the water tests have come out OK, your fish aren't in danger.  I guess it could be the airstone, maybe replace it and do a partial water change (no more than 1/3 of the tank).  then repeat the water tests just to make sure everything's OK.  Otherwise, maybe it would be something to do with the temperature - is the tank likely to get very cold where it is?  But cold water fish can handle water temperature dropping as long as it doesn't happen fast, so this isn't a problem to them.

[Noweia]

Sometimes overfeeding can cause cloudiness.