Cloudy Water

for the week of 4/9/98

Nobody likes cloudy water: not the aquarist, certainly not his/her spouse, and absolutely not the fish! Cloudiness is not only an unsightly but an unhealthy condition for the aquarium, as huge numbers of microscopic bacteria and algae use up precious oxygen.

Cloudy water is almost always the result of something organic decaying in the aquarium. Overfeeding is the most likely culprit; even a few uneaten flakes given each feeding encourage a bacteria or algae bloom. Decaying fish corpses or even dying plants can also lead to cloudiness.

The first step to clearing the water, then, is to find the source of cloudiness and eliminate it. A partial water change, including a thorough vacuuming of the aquarium gravel, will remove much of the decaying debris. The filter should also be cleaned or rinsed if necessary, and any decaying waste eliminated.

Feeding should be done very sparingly during the next few days, so as not to fuel another bloom. In fact, in cases of extremely cloudy water (for, example, if you can’t see through the aquarium the long way), it’s probably best to discontinue feeding altogether until the water clears. Don’t worry, fish can easily survive a few days without food,.and poor water quality is certainly a more immediate threat than malnutrition at this point.

Aquarium clearing chemicals – especially the newer “flocculents” that bind tiny bits of debris into bigger, easier to filter out clumps – can be used to clarify the water directly. In many cases, they result in crystal clear water in a few hours or overnight. However, if there is still a source of decayinmg organic matter, cloudiness will return shortly thereafter.

Submitted by: Jim Kostich

“Tip of the week” appeared regularly in 1999 and 2000.