Bryopsis look like little palm trees or like a fern. Bryopsis tends to attached and burrow deeply onto and into rocks and crevices, making it very hard to remove by pulling it out. Care needs to be taken when pulling it out in the tank, as it can splitter off and take hole in other places in the tank. It's best to remove the rock and scrub it outside the tank. Also elevating the levels of magnesium from the normal range 1,500 – 1,600 ppm seem to kill it as does elevate your pH to a steady 8.5 for three weeks seem to kill it too. Some fish, like Rabbit Fish, Foxface and Tangs will eat it.