Freshwater Clams for the Ornamental Aquarium

Welcome back Patty Little to That Fish Blog!

Clams and other bivalves are well known for their filtering capabilities, absorbing toxins and nutrients from natural waterways both freshwater and saltwater. While clams and their relatives are common to reef aquaria, there are also clams available for freshwater tanks. The clams offered most commonly by pet stores are Corbicual sp. from freshwater Asian waterways. They can be interesting and beneficial additions to freshwater tanks, so I thought it might be worth a little article to help anyone along that may be considering the addition of these inverts.

These clams grow to about two inches across, and may live for months or years depending on their living conditions. They range in color from golden tan to black, and sometimes accumulate algae on their shells. They can be housed in even small tanks, 5-10 gallons, as long as they have enough water movement, decent filtration, and are provided with supplemental food when necessary. These clams should thrive in temps from 65-82 F and will need somewhat harder water to maintain a healthy shell. They are also best suited to an aquarium with a fine substrate bed as they like to burrow into the sand. You will be able to see the clam’s siphon as it protrudes.

Clams feed by filtering detritus and nutrients from the water column. Depending on your tank, you may or may not need to supplement your clam with invertebrate foods, as in many cases they will take in what they need when you feed your fish and as they stir through the substrate. The result should be a cleaner and clearer aquarium.

Now for some cautionary notes. First, be sure that you house your clam with appropriate tank mates. Avoid housing them with predatory fish and other carnivores like many cichlids, puffers, rays, and bottom dwelling shrimp and crayfish that may agitate the clam. Though they are buried, their tissues are delicate and can be easily damaged, and if they are frightened or disturbed, they will not be able to feed and may starve. Remove your clams if you must treat your aquarium for any reason, particularly with copper based medications, as they cannot tolerate any copper in the water.

Though you may find freshwater clams and mussels in local ponds, streams, rivers, and lakes, it is generally a bad idea to collect species from the wild for use in a home aquarium. Wild specimens may be carriers of disease and tiny parasites that can be detrimental to captive fish. As they absorb toxins, these toxins may also be released into the otherwise pristine water you maintain. The other issue is that some bivalve species reproduce by releasing tiny larvae. These larvae may attach to the slime coat or gill filaments of your fish, and the resulting infection may be deadly. It is best to purchase clams from a reputable dealer so you know what you are introducing.

Finally, though it should be common sense, as responsible aquarists or keepers of any non-native species, clams and aquarium water should never be disposed of or introduced to waterways for any reason. Introduction of non-native species can have horrific results. Use caution and be responsible with any plant or animal you may not be able to care for by contacting other enthusiasts, pet stores, or authorities for safe solutions to finding a new home to prevent serious environmental impact.

Thanks Patty,

Until Next Time,

Dave