Urchin hitchhiker ID/advice

[musty baby]

Saw my hitchhiking urchin again tonight, and managed to get a slightly blurry but I think good enough photo of it.

I don't know squat about urchins, except that in the past I've had a knack for killing them. This one went in on a piece of live rock that was put in the DAY OF setting up the tank, prior to cycling, etc. I was SURE I'd be able to kill it, but I suppose not.

My questions are:

What is it? (reasonable guesses anyway, I know the picture is bad as it was taken in the dark, at the back of the tank, and it's only ~1" diameter)

Will this one day cause me problems?

It is currently munching away in a 75 gallon display tank full of LPS, zos, a few mushrooms, one porites rock and a crocea clam. I fully intend to go to a 200+ gallon tank and start keeping some sps within the year.

Thanks all

 

[dwhit0102]

It looks like a pencil urchin

The only problem that it could cause in the future is that it eats coral line I had one in my tank for a little while but he never damaged any of my corals. I think they look neat either way.

 

[SDguy]

Looks like either Echinometra mathaei or Echinometra viridis depending on where your rock is from.

 

[tibbs2]

Not a pencil urchin. Their tips are rounded. I'd keep it and only get rid of it if you notice it bothering your corals. Pretty cool!
Kind of looks like the type of urchin they make uni out of.

 

[thehedge]

Its Echinometra mathaei, aka Rock Boring Urchin. Its a VERY common urchin.

 

[sawillia]

I've got on and I've seen it grow now for a while. It gets along with everything and makes a fun night viewer....

My nephew loves it

 

[SVXH6]

i have had one in my reef for awhile now, he has not bothered any corals at all.. the only thing he seems to do is eat the corraline algae but i dont mingd, it seems to grow faster that way..

 

[fishome25]

yup, rock boring urchin, common hitchhiker