Fingernail Clams, Sphaerium corneum

Photo: Some fingernail clams on a hand. The few spiral shells are dead pond snails.

A couple of years ago, we started noticing some small white, translucent clams living in the bottom of some of our vats. I idly wondered what they might be. It wasn’t until I read an article by Sara Sneath a reporter with the Victoria Advocate, which is a newspaper serving our area of Texas, that I found someone to identify them. Sara wrote an article about mussels (clams) in the area rivers (https://www.victoriaadvocate.com/news/2016/dec/10/freshwater-mussel-research-underway-in-the-guadalu/). I figured her experts could help and emailed Sara with photos. The answer from her expert, Charles Randklev of Texas A&M (Hook’em Horns! I’m a UT Austin grad, but have found Aggies to be good for something occasionally) was, “Hi Sara, these look like fingernail clams to me, which is a group different then the unionid mussels.” With that information, I searched the internet and, after viewing photos, agreed Charles was right. It was probably Sphaerium corneum, the European fingernail clam.

I have no idea how they got into our systems. They are reportedly introduced into North American waters. Maybe they hitched a ride with some fish or plants. Although, it’s also possible they came in from outside on frogs, snakes, or turtles that occasionally colonize our greenhouses. In an event, they seem to have settled into the ecosystem. Since clams are filter feeders, I wonder if they could be used in filters to cleanse the water of microorganisms. They seem to thrive in vats that also have Tubifex worms (see my recent blog about this worm: http://goliadfarms.com/tubifex-worms/).

I bet puffers and other snail eaters would like them.

Good fishkeeping!