I remember seeing a thread here awhile ago about all those moss balls (scientifically identified as the same kind found for sale in pet stores) that washed up on Australia's coasts, and speculation as to whether or not moss balls could survive in saltwater. A couple days ago I decided to try it. So far, so good. The moss ball looks healthy green, and probably appreciates the tumbling it gets it my sump. Its along side some chaeto algae and some ulva. I wasn't sure how to acclimate it, so I just threw it in there. Again, so far so good, which leads me to wonder, if it couldn't thrive in saltwater, wouldn't it have died off by now, as most strictly freshwater plants would in a saltwater environment?