aquarium filters
...that aquarium filters are necessary to support life as aquaria are relatively small, closed volumes of water compared to the natural environment of most fish?
...that <b id="mwDrg"><a class="mw-redirect" href="./Filter_(aquarium)" id="mwDrk" rel="mw:WikiLink" title="Filter (aquarium)">aquarium filters</a></b> are necessary to support life as <a href="./Aquarium" id="mwDro" rel="mw:WikiLink" title="Aquarium">aquaria</a> are relatively small, closed volumes of <a href="./Water" id="mwDrs" rel="mw:WikiLink" title="Water">water</a> compared to the natural environment of most <a href="./Fish" id="mwDrw" rel="mw:WikiLink" title="Fish">fish</a>?