We have just changed from sand to stone, as its easier to clean.
However when we got home tonight, our Oscar and friends have very kindly chucked a few stones in the filter and broken it and is now making a horrible noise!

I know this is a common thing with Oscars, so has this happened to anyone else and can you suggest how to get the stones out, etc??

What type of filter is it? It shouldn't be too difficult to remove them.

Its a Juwel filter. Couldnt tell you what model though?! sorry.

Is it the separate 'in-tank' Juwel filter? Or is it part of an all-in-one aquarium setup? If its making noise I would assume it has an impeller/motor...take it out and open it up just like you do when cleaning...check the impeller housing. I'm surprised it didn't just get caught in the sponge.

You might need to purchase a new impeller...

www.juwel-aquarium.de/en/articleinfo.htm?matnr=85072

If its the only filter and it's broken time is of the essence.

Take it apart including the impeller to remove any stones, then refill and try to get it working. If it still wont work get another filter ASAP (leave the filter switched off but full of water). When you get the new filter transfer the media to the new filter (if it only has sponges then put them in the new filter).

The filter should have some sort of grid to stop stones getting into the filter. Are you sure its stones, could it be sand from where you removed it, or a coincidence of the filter failing at the same time you changed the substrate

If the filter is the type that is in the tank, then it wont be enough for large oscars so you will need to buy an external cannister filter anyway. Get one rated for a tank twice as big as your tank (if you have a 100g tank get a filter rated for 200g)

You say you have oscars and friends- what fish do you have and how big is the tank