A living filter for mature tanks — freshwater clams pull suspended particles straight out of the water column, burrowed contentedly in your substrate.
A freshwater clam is a filter feeder — it eats microscopic particles suspended in the water, which means it needs a mature, established tank to thrive — it may starve quietly in a pristine, over-filtered setup. Give it a few inches of sand or fine gravel to burrow in, stable parameters, calcium-rich water for its shell, and supplemental feedings of powdered or liquid invertebrate food if your water runs clear. In the right tank, a clam is a fascinating, genuinely useful oddball.
Suspended microscopic food: green water, infusoria, fine particles of decaying matter, and powdered invertebrate foods. They cannot eat algae off surfaces or scavenge leftovers like a snail — if it isn't floating in the water column, a clam can't reach it. In most home tanks you should target-feed a liquid or powdered filter-feeder food a few times a week, dosed near the clam so the current carries it over.
Moderately, and for one specific reason: feeding. Water quality and tankmates are rarely the problem — starvation is. Clams do best in mature, lightly stocked tanks that aren't scrubbed spotless, ideally alongside fish whose feeding stirs fine particles into the water. If your tank is under six months old or you run heavy mechanical filtration, wait or plan on regular supplemental feeding.
Down. Clams burrow into the substrate with only the edge of their shell and their siphons exposed, and a settled clam may not move for weeks. That's normal. Check on it by looking for a slightly open shell with siphons visible; a dead clam gapes wide open and won't close when gently touched.
