An aquarium filter is a device that helps keep the water in a fish tank clean and healthy. It works by removing dirt, debris, and harmful substances from the water, ensuring that fish and plants can thrive. Filters come in different types, including mechanical, biological, and chemical filters, each serving a unique purpose in maintaining water quality. Using an aquarium filter is essential for any fish keeper, as it helps prevent the buildup of toxins that can harm aquatic life. Regular maintenance, like cleaning or replacing filter media, is important to keep the filter working effectively and to provide a safe environment for your aquatic pets.