Rock Boring Urchin - Verdict???

[djordje]

While my gulf aquacultured rock is still getting acclimated, I've got new visitors popping out everyday. I found a rock boring urchin last night and separated it into a plastic container, within the tank. It's about the size of a quarter. I've been told that these are destructive in a reef setup, others say no. Before, I drop this thing off at the LFS, some opinions would help.

[tdwyatt]

I have one that I have had for nearly 7 years (at least) that I got as a hitch hiker from the rock that I bought at the 1999 MACNA in Louisville (From Joy at the old Premium Aquatics, I think). One rockborer is not going to devastate your tank, mine bored a place under some rock and uses that as a hiding place during the day (never see it in the tank roaming around unless it is at night)

I'll try and get a photo today sometime, it uses the same place every day to hide.

[djordje]

Thank you. I'd love to see the photo. I have some natural big holes already in the rock. I suppose that is where this thing came out of. Is all of your coralline algae intact? I have some nice sponges and I don't know if these things eat that, or are strict algae eaters? My rock is very dense too. Do these have the strength to knock something over? Will they disturb corals and anenomenes?

[tdwyatt]

Yes, they will eat some of the coralline, but because all urchins are such messy eaters, they actually oimprove your coralline coverage unless you only have one small piece of rock and that is all the urchin has to eat. They actually will eat biofilms in general and many fillamentious algaes and clean the rock all the way down to the clean substrate, where they corallin algae can then get a foothold for new growth.


AUrchin in question was in the pic of the following system for almost 5 years along with a Diadema and a Mesphillia spp. urchin, photo courtesy of Dick Vance:



I've never had an issue with getting coralline algae to grow, regular 10% water changes, an occasional boost of alkalinity, and a continuous topoff kalk drip for that particular system was all that was needed to maintain good growth of corals and the coralline.


HTH

[djordje]

From the sounds of it. One urchin may be beneficial in the reef??? I have 235 lbs of rock in a 125 gallon. It doesn't sound like it'll destroy my rock. What about my sponges?