Bio-Filter Cleaning Question

I have 5 small Koi fishes in an aquarium. How often must I clean the aquarium? I do have a bio-filter, but the water is becoming a bit murky. -Natasha Your aquarium should be cleaned weekly to keep the water clean and clear. If a weekly cleaning gets to be too much, consider adding additional filtration to your aquarium or cutting down on feeding a little bit. Share: Del.icio.us Digg Reddit