Tips for Clear Fish Tank Water

Healthy fish-tank water is clear, not cloudy.

Healthy fish-tank water is clear, not cloudy.

Fish are fairly low-maintenance, but if you let that slip to no-maintenance you could wind up never seeing your fish’s cute little face again. Prevent cloudy, murky water with a filter and some tender loving care and you’ll be rewarded with a crystal-clear tank and a contented pet.


Your fish-tank water won’t stay clear for long if you don’t have a filter. Dirt and debris mounts up in a couple of days and if there’s nothing to take care of the waste it just floats around looking gross. It’s also worth mentioning that your fish probably doesn’t enjoy swimming in his own poop either, so do the right thing and buy him a tank filter.

Don't Overfeed Your Fish

It’s easy to overfeed your fish, so if there’s uneaten food in the tank after 5 to 10 minutes, scoop it out with a net instead of leaving it in the tank for dessert; fish don’t eat dessert. Little and often is the best feeding routine; leftover food decomposes in the gravel and clouds the water so always make sure your fish has fresh food and remove any excess before it turns to a mushy mess in the bottom of the tank.

New Tank Syndrome

New tanks are often cloudy, even when you maintain them properly. A milky white haze in the water is usually caused by a bacterial bloom, but it won’t harm your fish if you change some of the water regularly. It’s is a common side-effect of the tank water settling down and reaching chemical stability; carry out partial water changes twice a week and it should disappear of its own accord.


Green water is caused by algae. Most tanks have a few specks here and there and fish do like to peck at the slimy stuff now and again, so small amounts are nothing to worry about if you keep it under control. However, if you provide too much light the algae’s growth accelerates turning it into an unsightly menace. Don’t place your fish tank near a window and keep your tank lights on for between 10 and 12 hours a day at the very most.

Chemical Intervention

It’s easy to solve the majority of fish-tank water problems naturally without the need for potions, but if you have a persistent cloudy water problem you can always resort to a chemical flocculant if all else fails. Flocculants bind together very small particles of debris in the water, making the clumps large enough for the tank filter to snag them.

General Maintenance

A clean tank is a healthy tank, and regular maintenance is the key to clear water. Prevention is always better than a cure, so keep the causes of cloudy or dirty water at bay and you should have permanently crystal-clear water and a happy little fish.

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About the Author

Alex Burgess has been a professional writer since 1990, specializing in travel, herpetology, lifestyle, fashion, health and fitness. Her work has appeared in various British newspapers, magazines and international online publications. Burgess studied design before working as a journalist in England.

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