Just purchased this rock that has several mushrooms on it. While acclimating this popped out. What is it? Good or bad? Will reef dip kill it and everything else bad? I also got a emerald crab too. Free hitchhiker
It is a nudibranch and it's very hard to tell if it's good or bad, since there are so many different types.
Here you go...here's a ton of images to look through when you are bored- Nudibranch and Sea Slug Photos Collection » Nudi Pixel
You can just pull it off with some tweezers if you like.
I sent an email out regarding mine to liveaquaria. Hopefully they have some info on this little bugger. I have a hard time believing that a bad nudibranch came in on an order from them, but I was also surprised by aiptasia on the same rock. So we'll see.
I dont have a hard time believing they dont dip or inspect, but with things coming out of their diver's den would be in a setup where some bad critters wouldn't be. It is pretty obviously on aquacultured rock.