Cloudy Aquarium Water

Updated April 20, 2020
Author: Mike - FishLore Admin
Social Media: FishLore on Social Media

Do you have cloudy aquarium water in your fish tank? Here are the most common types of cloudiness:

Read on to find out how to deal with each of these water quality issues.

White Cloudy Aquarium Water

If you have a white cloudy fish or gray cloudy water in your fish tank and you have just set it up, it could be the dust from the gravel or sand. Be sure to thoroughly rinse your substrate before adding it to your aquarium. This can be difficult to do with sand but the dust particles should settle in a day or two.

If your tank has been set up for a short time this may be the result of a bacterial bloom that happens in a newly set up tank or when too many fish were added too soon. This cloudy situation will correct itself when a sufficient amount of bacteria establishes on your biological filter. See the Nitrogen Cycle for more information on this process.

You can help keep your tropical fish from getting stressed by performing 25% water changes daily and feeding them less until the nitrogen cycle has finished.

Green Cloudy Aquarium Water

Usually the result of an algae bloom. Read up on how to control aquarium algae. The green cloudy water will not harm your fish but it is not the most pleasant thing to look at. This happens because of the amount of nutrients and the amount of light entering the aquarium. Your tank water is nutrient rich, which may mean that you're feeding too much, your tank may be overstocked or you're not doing enough water changes or a combination of all the above. The main problems are usually high nitrates and phosphate levels. If you have a saltwater aquarium consider using a protein skimmer and biopellets. Avoid placing your aquarium where it could receive direct sunlight. Direct sunlight will add fuel to the fire so to speak and direct sunlight will cause temperature fluctations as well.

To correct this problem, perform 25 percent water changes daily, rinse out or replace the filter media to reduce the amount of nitrates, feed your fish a little less and leave your tank light off for a few days or until the water clears up. If you do practice good aquarium maintenance and still have algae problems, look into testing your tap water. You may be introducing nitrates and possibly phosphates into your tank via the water changes and not even know it. Also look into keeping live aquarium plants which will compete with the algae for available nutrients.

Pond keepers sometimes use a UV Sterilizer on their outdoor ponds to help control algae growths. While we agree that these sterilizers can have a positive effect on the algae growth in your tank, there are better, less expensive methods to use for controlling algae in the aquarium and we recommend you try some of the ideas presented above.

If that doesn't work, as a last resort, you could use Aquarium Pharmaceuticals Algae Destroyer. The algae destroyer should clear up the algae problem quickly. Please use as directed on the bottle. This is just a quick fix and we recommend that you figure out what's causing the algae problem in the first place.

Yellow Cloudy Aquarium Water

Yellow aquarium water can be the result of several factors. Fish waste, driftwood, decaying plant matter and other dissolved organic carbons (DOC). This often happens in tanks that have new driftwood and it is because of the tannins in the wood being released into the water. This should subside after the driftwood has been in the aquarium for a couple of months.

To best way to fix the yellow coloration of your tank water is to perform more frequent partial water changes along with the use of activated carbon. Activated carbon has many uses in an aquarium filter including removing small amounts of DOC, removing water smells and making the water look cleaner or polished. Try to change out the carbon on a regular basis, at least every 3 to 4 weeks if not sooner.

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