Sorry for the previous post guys. Got mixed up with the shell kingdom. I mean I plan to put live mussels in my sump tank to filter my reef tank water. They strive in breakwater rocks in not so clean water & warm water. Even in water with oil spills from ships. They are attached to rocks; doesn't move anywhere once attached). Rely on nutrients from water passing by. Anybody with exp? Do they need light? Or is this the first try?