Re: *****Advice please*****
#6
The filter will smell yes because this is where all the muck is trapped. You can/should clean it out every so often using bucketed pond water, NOT a hosepipe.
That's a lot of fish for a pond that size, depending on their size you could be close to overstocking.
When the water temperature drops, i.e winter the fish become less active and don't have as much as an appetite as they do in the summer months. You should be feeding your fish as much as they will consume within 5 minutes, twice a day in the summer then cut this down to only one time a day during the colder months.
Providing your pond isn't indoors in a shed etc the fish would most likely survive without being fed because of natural foods that fall into the water, but still it is adviseable to feed them.