just follow the directions
Filter a fish? Do you mean filtering a fish's tank? Well you have to filter any fish's tank.
Yes you do need a filter in your fish tank ifyou don't the tank will build up dirt and the fish will die. Also when you get a fish tank you need to clean it out then fill it with water then put the filter in and wait 24 hours. This helps to ensure that the tank is somewhat stable before adding fish.
The filter removes the fish waste and some of the other impurities.
A filter...
Then your filter is not on.
The charcoal filter in a fish tank should be changed every 2-4 weeks to maintain water quality and keep the tank clean for the fish.
A filter in a fish tank helps provide oxygen by circulating and aerating the water, allowing for oxygen to dissolve and be available for the fish to breathe.
no filter because for smaller fish it can hurt or even kill them and for the old filter use bigger fish
yes
Yes
ALL fish need filtration.
Freshwater setup: MUST HAVE: Tank, filter, filter pads/media, heater, light, fish, water, electricity, fish food, place to put tank NICE TO HAVE: Substrate, decorations, tank lid