Water Has Gone Slightly Cloudy

[zain611]

Just noticed that my tank water has gone a bit cloudy and was like this since yesterday and i suspect it was my corys as yesterday morning i didnt feed them so i think my corys got mad and were trying to dig everywhere trying to find food so it sturd up the stuff

 

[MBOU]

Emergency water test methinks!! Cloudiness is a worrying sign as it could well be a Nitrite spike!