So i bought a bunch of livestock from a guy shutting down his tank. He gave me a bunch of rocks from his tank, some corals, and a lot of snails. Anyways, i got this mushroom looking coral that is very hard and I don't know what it is. Also, his rocks have these dark green things that look like soggy bags (picture 1 and 2, i point at it). The rocks also have these red nails like things that are hard and can poke you or break off. What are those things? Should I simply wash the rocks down with vinegar and then hot water to be safe or are those ok?