I may be rather new to this site but I agree whole heartedly with the moderators. I was rude, MSG. Also, I, having kept muscles collected from my area for nearly a year before, can say that there was nothing that I did for them except add food. they just filter feed anyway. I had mine in a gravel based tank and they did great, under the gravel. However, back then I was a noobie to this fishy world. It makes perfect sense for the need of calcium in the water, and if you have rocks in your water, then you may not need to worry about it.
I just have to add that many people keep mussels and clams as pets, and would be very offended at what MSG said. I offended at it as well. This is a fishkeeping site, where people come to get advice about their pet and to gain knowledge. I simply do not see the point of posting pictures of dead clams on a thread asking how to care for clams. And it is no different from your dog, or a chicken, or a fish, or a cow, of even a leech. They are all animals, and someone out there cares about them.
I have had them before as pets and it was fun watching them"dance" around looking for a new place to dig and eat. But yea the tank needs to have a high flow rate and lots of sediment in the water for it to eat.
Ok I think we have all strayed away from the main question of :
What type of mussel or clam is it?
He did not ask for opinions on the clams/mussels living conditions, he stated that it has been living in his tank for about 8 months now, so the ones who keep telling him to better the clam/mussel conditions are late.
I know nothing about mussels or clams, but wanted to say that, you have a very neat little pet there. I have always thought they (mussels and clams) were unique and beautiful in their own way. I like to watch them stick their.. hand, foot, whatever it is, out. Its so darn cute.