- Cloudy water in a fish aquarium looks like a whitish, green or brown haze in the tank. Instead of particulate matter that floats about and is usually picked up by the filter, cloudy water adds an overall discoloration to the tank.
- White cloudy water is caused by an ammonia spike, bacterial blooms, faulty ornaments or added chemicals. Green haze is caused by algae colonies. A brown-tinged cloudiness to the water can be due to bacteria caused by driftwood in the tank.
- Cloudy aquarium water can have a detrimental affect on fish and aquatic plant health. Ammonia spikes or bacterial blooms are especially dangerous, and must be eradicated quickly. Deteriorating ornaments can poison the water, and dust can clog filters quickly. Of course, cloudy fish tank water also looks horrible.
- Prevent cloudy fish aquarium water by rinsing all ornaments and substrate well before putting them in the tank. Cycle a new tank gradually instead of introducing many fish at once to avoid a drastic ammonia spike. Vacuum gravel frequently and change the filter media as needed.
- A fish aquarium's water can become cloudy very quickly if the cause is chemicals or an ammonia spike when the tank is new. Fixing the problem can be time-consuming. Frequent water changes and vacuuming will help, but they must be done over a period of time so as to not shock the fish.
