pencil urchin

1journeyman

1journeyman

Active Member
I love this hobby.
So I just saw for the first time a small pencil urchin that must have hitchhiked in on some live rock (6 months ago).
Are they reef safe or should he/she be exiled to my refugium.
 
bang guy

bang guy

Moderator
Can you describe it? Pencil Urchins are carnivores and not reef safe. Make sure that's what it is before you banish it though.
 
mudplayerx

mudplayerx

Active Member
Are you sure pencil urchins are carnivorous? I was under the impression that all urchins had "Aristotle Lantern" mouths that were used to scrape micro/macroalgae off of rock. Just curious.
 
1journeyman

1journeyman

Active Member
Pretty sure it's a pencil urchin Bang.. light brown, round body (about the size of a marble right now) with short blunt tip spines that he/she slowly moves around as it is currently moving under one of my rocks.
I bought uncured live rock from Tonga, Fiji and the Caribbean so not sure which it came in on.
 
1journeyman

1journeyman

Active Member
Umm.. dang it. According to Shimek's Invert guide it's a Slate Pencil Urchin (Looks just like it.. although it could be another variety of Urchin)
And Bang, as always, is correct. The guide says it will eat sessile inverts as well as motile ones that they catch.
good news is the book says they return to the same hole each night so I should be able to catch him easily.
 
boom215

boom215

Member
can i borrow this thread instead of starting a new one. my girl was at the store the other day and called me and said guess what i got i was like what. she was like something for your tank so i was like yay. its a small purpleish colored urchin. short spikes no longer than in inch. what kind is that? i only have a yt in the tank with him. its a 75g? thanks
 
ophiura

ophiura

Active Member
Definitely DO NOT TRUST true slate pencil urchins. However, DO try and postively identify it as common names are interchangeable and misleading!! Most hitch hiking urchins are Echinometra and are generally considered OK. They can be bulldozers, and some can cause trouble...but most will eat algae and some coralline. While they do eat coralline it is considered to help spread it in most tanks.
 
1journeyman

1journeyman

Active Member
Well, the little urchin didn't return to his cave last night.. so it may be months before I see him again.
I'm far from an expert on urchins.. but this one clearly had the blunt, round, thicker spines I'm used to seeing on urchins.
I'll watch him. I only have a xenia, encrusting gorgonia and a toadstool coral right now. Most of my snails are bigger than he is so I'll watch and see. If he causes trouble I'll just move him to my refugium. Plenty for him to munch on happily there.
yeesh... 25lbs of Caribbean live rock and I am blessed with one mean hitchhiking crab (now in the refuge), one mantis and this guy. What's next? Couple of Blue Ring Octopi?
 
rsargent

rsargent

New Member
I have a pencil and he has pretty much consumed half of my purple gorgonian. Didn't do my research first, like Mr. Limpet recommends. I will next time, but as for now, what do I do with him?
 
flower

flower

Well-Known Member
Quote:
Originally Posted by boom215 http:///t/179843/pencil-urchin#post_1323482
can i borrow this thread instead of starting a new one. my girl was at the store the other day and called me and said guess what i got i was like what. she was like something for your tank so i was like yay. its a small purpleish colored urchin. short spikes no longer than in inch. what kind is that? i only have a yt in the tank with him. its a 75g? thanks
LOL...Like I'm glad you like the word like so much.
What you describe is a pincushion urchin. They are reef safe, but they knock everything over like a bulldozer, and they also feed on the pretty purple on your rocks until there is nothing but bare rock.
Urchins need tons of algae to survive...in a tank under a year old I would pass on it. If you're smart, you will not allow anyone else to stock your tank. You should do your homework on all critters you want. There is nothing wrong with choosing a critter with your girlfriend and getting something she likes, but I would put the brakes on when it comes to just purchasing you a critter gift. JMO
 
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