Filter Worms..

[Bad Jeff]

Hello,
I have a 10 gallon community freshwater tank, and this is the second time this has happened. I clean the tank weekly, as well as the filter, and this time there were these brown small worms all inside the foam filter. What causes this? If i wash out the filter really good they go away, but this is the second time they have come back. Thanks for any ideas.
Kristin

 

[QTOFFER]

The worms are probably planaria. They often hitchhike their way into the tank with plants. Usually, large numbers are due to excessive nutrients in the tank. They're harmless to you and your fish, but they're kinda gross and their presence may indicate a problem with water quality.

Do you know the water parameters (ammonia, nitrite, nitrate)? Lots of uneaten food (which the planaria feast upon) leads to high ammonia, which can harm your fish.

Do you vac the gravel weekly? There may be lots of gunk in the gravel that is feeding the planaria too.