my black spiney urchin ate all coralline alage off my rocks. my friend had a pencil urchin that dose the same. it also stabbed my clown one time when the clown was spooked and swimming away very fast and slammed into it. i dont know about the urchin you have just those two. hth
i traded him back in but if your attached to it leave him. i dont know about having it with corals it may poke them and hurt the corals at the time i didnt have and corals. maybe someone else can help out with it. but i know it did eat my coralline alage very quick. it is now about 6 months later and just starting to grow back.
Julie,
The only thing I know about problems with Urchins is that they can dislodge rock and corals fairly easy, and if in a small, confined area the can also pierce soft corals and anenomes..
And that if you allergic to wasp/bee stings, it probably isnt a good idea to get the stinging kind, but pencil urchins are cool, and dont sting..
~Susie
I have an urchin in my tank. He came in on a piece of gulf LR and I never took him out. He is only the size of a quarter, and I rarely ever see him. They do eat coraline algae, but I figure this guy is to small to do any real damage. I did watch a TLC program about them and apparently thousands of them can leave a reef looking like the site of a nuclear blast after 6 months.
Congrats on your new aquisition!
The main problem with urchins, is not them so much eating coralline (probably encourages growth), but rather them KNOCKING THINGS OVER!
Does anyone know how fast these things grow? Like I said mine is only the size of a quarter and really can't move any of the rocks in the tank, but how long before I have a monster anemone nocking stuff over?
I had two hitch on my lr. They are long spiked and black. The first one was the size of a dime and the second half that size. 6 weeks later they both have grown 3-4 times their original size. Their growth rate is incredible. There is some coraline that has been eaten but they haven't caused any significant damage. I am afraid of them hurting my corals but as of yet there haven't been any problems. I don't have the heart to trade them in.