urchin

I’ve been battening this alage on a new tank for about a month now not sure what kind it is. But it’s extremely tough, I can’t scrub it off or pull it off. I also cannot take the rock out of the tank as it’s epoxied into one structure. My tuxedo urchin does eat it but only little bit at a time...

I saw a thread around here a few weeks ago that had pics of all different clean up crew critters and how they work in the aquarium. I tried searching for it but can’t find it. Anyone know where it might be hiding and can link it ?

My live rock (TB Saltwater) came in with several urchins. This one has doubled in size since I first noticed her (2 weeks, maybe) - she carried shells around and has pale spines. Any ideas? And is this one a black longspine? She doesn't carry things around and she's growing very fast, too...

My yellow tang periodically crashes into my longspine urchin in his travels around the 210. Once in a while it looks like he gets poked pretty good, the urchin looks likes he gets moved over about an inch. Should this be concerning? Are either of them getting hurt? Is my tang dumb? Urchin is...

A replaced my original tuxedo urchin a couple of weeks ago with a beautiful white tuxedo and since it's arrival my Potter's Angel has slowly been picking away at it's spines. It's 1/3 bald at this point. Has anyone seen this behavior before? I've tried to dig around and find something on this...

I noticed my Pencil Urchin was sitting on top of where I have some Mushrooms. I got some baby mushrooms there, 1 that was a morph between some, and they are gone. Anyone have an issue with this?

Anyone know what this guy is? He looks a bit weird right now as he went into defense mode and stuck most of his pins straight up. He has a black body, with the 5 black lines separating his body into sections (just like any old tuxedo urchin.) but his pins are half striped white and maroon/red...