please help with my fish tank ?

[christina w]

i have had a tropical fish tank set up for 6 months everything being going ok but my fliter running slower than usual and not blowing out as many bubbles as usual is this normal ? HELP PLEASE its 54 litre there is 8 fish and some new swordtail babies dont want to lose them to i get a new fliter ? air pump?
have cleaned and took it apart a few times and was ok i try agian thanks

[betta124]

like take it a part, may be something clogged in it, this is very common, with a little fixing and looking should work again.

[Sibyl]

Once a month I clean my filter- by clean, I do not mean scrub everything down and replace the cartridge- I mean that I remove the intake tube and take it apart to scrub it. A filthy impeller could be slowing you down.