Please can you suggest how to get rid of tiny white flies that are hatching daily. They don't die even when I try to drown them. The may be incubating in the corner as I have a corner unit Juwel filter system. They also dont mind the light fitted in the lid. When I lift the lid back and front they fly out and land on nearest wall where they stay until I vacuum them up about twice a day. I started having this problem since about april/may time. I clean and wipe down every corner and crevice when I clean approx 3-4weekly intervals. I have an assortment of fish such as gouramies, mollies tetra, 2 large clown loach and 2 large Denibarbs. which I've had for 5 years.The top feeders are not interested in eating the flies, maybe they can't see them because they are so light they just rest on the surface water so they are able to fly when the lid is lifted. The tank is 3 years old and well maintained. Have you any suggestions other than transferring all the fish into a temporary tank tank and cleaning from scratch? It took ages for the clown loach to trust me when they were moved into this tank 3 years ago.
What causes white worms or larvae in a fish tank?
Small white creatures appearing in your aquarium are usually detritus worms, planaria, or fly larvae. These organisms thrive when there is excess organic waste in the tank. They are often harmless, though their presence suggests conditions that could use some attention.
You might not notice waste building up in the water itself. It often accumulates inside the filter, where debris collects over time. This creates an ideal breeding ground for larvae and worms, hidden away from view.
Cleaning your tank every three to four weeks may feel thorough, but it usually is not frequent enough to prevent this kind of build up. A lighter clean once a week, alongside your regular deeper cleaning routine, can help keep waste levels under control. Using a gravel vacuum during water changes will also remove debris trapped in the substrate.
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Start by rinsing your filter medium in old tank water rather than replacing it entirely. Complete replacement disrupts the beneficial bacteria that keep your nitrogen cycle stable. If the medium is heavily soiled or degraded, replace only a portion at a time.
Next, remove all the non electronic parts of your filter. This includes tubing, plastic casings, and any other components you can safely detach. Clean these parts with hot water or an aquarium safe solution. Avoid boiling, as this can warp or weaken plastic components. Once cleaned, they should be ready to go back into the tank.
The process should take around ten minutes. Most fish can manage without the filter running for this short period, though keep an eye on them for signs of stress.
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Preventing future outbreaks
Regular maintenance is the most reliable way to stop these organisms returning. A weekly light clean can make a noticeable difference, even if you only have time for a quick once over.
Keep an eye on your filter in particular. Waste tends to accumulate there faster than elsewhere in the tank. Checking and rinsing filter components regularly will reduce the chances of creating conditions that attract unwanted guests.
Feeding your fish the right amount also helps. Uneaten food sinks and decays, adding to the organic matter in your tank. Most fish do well with small, measured feeds rather than large portions. Maintaining stable water parameters through regular testing supports overall tank health.
When to seek further advice
If the problem persists after cleaning, it may be worth consulting a specialist aquatics shop. Staff at reputable retailers can often identify whether there are other factors at play, such as water quality issues or overstocking.
For general guidance on keeping fish healthy, the RSPCA and OATA (Ornamental Aquatic Trade Association) offer helpful resources on their websites.
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