I have a variety of snails, glass shrimp, amanos. Tons of other inverts, but they are SW.
And, just yesterday I was able to sit in on a class on FW mussels, also known as FW clams. After listening to an expert, I have come to the conclusion that they really are not a good candidate for the aquarium. First, they are filter feeders. While this is often interpreted to mean they will help clean your tank water, what really happens is they starve because there are not enough solid organics in the water for them. Second, mussels are considered 'canaries' in streams--they are indicative of water quality simply by their presence. Mussels will not live in waters with even very low levels of toxins (nitrogen being on the list of toxins). Even with daily water changes, the presenter had problems keeping them alive for more than a few months. Third, only a few species remain above the surface, most bury themselves into the substrate with only their intake and out flow tubes showing. Hard to keep track of them and their health. Many species will not bury themselves in gravel substrate, so a deep, muddy bottom is needed--not great for most fish tanks.
Fourth, and possibly more significant, the larval stage of mussels parasitive fish. Of the 360 native species, 359 parasitize fish--one parasitizes larval salamanders. Most are specific in their host, but the hardier species can parasitize pretty much any fish that's available. Like ich, severe infestations will kill the host.
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