Cloudy Water


Cloudy water is caused by a bacterial bloom in the aquarium. A bacterial bloom is when the bacteria in the tank multiplies in such high numbers that they cloud the water. Bacterial blooms are caused by excess nutrients in the water.

This can happen when:

  • A tank is first set up.
  • New fish have been added to the tank.
  • After a water change.
  • Continuous over feeding.
  • Replacing or cleaning a filter.

The bacterial bloom itself is not harmful to fish, but the increased amount of bacteria will use vast amounts of oxygen, and may suffocate the fish. When a bacterial bloom occurs, fish are quite often seen at the surface of the aquarium gasping for air.


If left alone the cloudiness will go away, though this can take anywhere from a few days to a month. Control of the amount of nutrients in the water will keep the water clear, and this is easily done with regular water changes. If the problem water originated with excess food, then a 50% water change will have to be carried out, & all the uneaten food removed.

The water change may have to be repeated 2 or 3 times. The regular use of a bacterial supplement will prevent a bacterial bloom. Chemicals are available which quickly remove the bloom from the water. These are fast working and are not harmful to fish or plants. Quick Clear and Accu Clear are good remedies.

Interpet Quick Clear Link

Fluval Quick Clear Link 

API Accu Clear Link



Urmston Aquatics