Can someone please tell me what this is? The green plant with long threads and slightly feathered at the ends. I got it from rusalty. I actually bought a fire red Macroalgae, but this made its presence known in a couple months of being in my tank. It's growing on the same rock. It's growing about 4-6 inches a week. I like it, but never saw it before, not even snorkeling around the keys. Yes, a juvenile seahorse. I raised a bunch.