White feathery filaments after cleaning pump?

[TheUterati]

I have a fairly new tank set up (end September 2016). 200 litre tank. I do 15% water change every week, and the same plus clean the Fulval filter every fortnight. Change carbon, etc on schedule.

The last couple of filer cleans, when I have started the filter up again, it has expelled white feathery filaments into the tank. What might these be and do I need to worry about them? How do I get rid of them?

I test the water every couple of weeks, and it is absolutely fine. Water is clear, and doesn't smell. No algae. Fish are all happy (the black mollies are even breeding).

Do I need to worry?

Mine does the same, I think it's just fish food&poop that's been broken up by the filter.

Thanks! I am still fairly new to all of this, so I am still finding my feet when it comes to what is 'normal'.

When I did the water change yesterday, I held a net over the output when I started it up again and managed to trap and remove a lot of the gunk.