What do common sea urchins eat?

[FishyMel]

I just got a purple common sea urchin. I thought he might clean the back of the aquarium on the glass since I get an algae buildup and it is hard to there to clean it. So far the urchin just moves around on one of the live rocks. What do they eat? Do I have to feed it special? TIA

 

[Nitrate]

Im not familiar with that particular urchin, but mine will go where the food is. If they have plenty to eat on a rock they wont bother moving to the glass.

I have 2 long spined and 1 pincushion and they rarely get on the glass in my aquarium, but at the LFS where the tank has few rocks they spend most all of their time on the glass.

HTH

 

[quarryshark]

Well they will eat some green algea. They also like coralline algea. Thats what he is probably doing on your rocks.
You will see him everywhere, glass, rock, substrate, etc. They are good at cleaning up uneaten food as well as crab and shrimp molts.
I also once a week feed mine a small strip of Nori. They seem to enjoy it.
Have fun!!

 

[FishyMel]

Will he completely destroy my live rock? It looks like where he was sitting yesterday, the rock is stripped down to absolutely nothing. I don't want all my liverock eaten. This is starting to scare me. I think he might be hard to control.

 

[quarryshark]

Thats why I target feed mine the nori. It does help.
The Urchin is/will be an asset to your tank, just feed him once or twice a week and enjoy. They are cool critters.

 

[FishyMel]

Does the target feeding of t he nori keep him off the liverock. Mine moves really fast. I can put him on the ground way away from the rock with shrimp or something, and he will bypass it to get back on the liverock. He stripped down a 22 pound rock to complete white in only a week. Multiply that by 6$ and you can see the damage he is doing. We took him back to the fishstore last night and got our money back. I only have 90 pounds of liverock and it was sooo expensive. I am sad that I had to give him up. Tell me if you really are successful at keeping your urchins off your rocks completely and if I acted in haste, by returning him. BTW He was about 3 inches in diameter(huge) and bright purple with lots of long thin spins. (Is that a pincushion?)

 

[Atari]

The thing to remember is all individuals are different to some degree. If the one you had was a nuisance then you did the right thing.

 

[quarryshark]

I have a longspine, 2 pincusion(one white, one purple), and a blue tux urchin. The one you had sounds like a pincushion, too hard to tell without a pick. Look in my gallery, I have a pick of my purple pincushion stealing my nori clip. They can be quite mischievous.
Is it possible to keep them off the rock? No way, they go wherever they like. They do eat some of my corraline, but frankly mine seem more interested in the green algae. Maybe I am just lucky. Like Atari said, each is an individual, maybe another would do less damage.
I just happen to like inverts and am willing to put up with a little more than some. As long as they don't hurt my fish.

 

[Atari]

Q-man you make a great point.. there's no set rules for what we should and shouldn't keep in our tanks. Everyone should make up their own mind based on their own situation and preferences. Diversity is paramount!

 

[XXFirefighter]

My blue tux cleans my rock and rarely makes it white, but when he does, it grows back fast..

 

[Lindsikins00]

I have two urchins, I did notice that they ate the coraline algae but when I started clipping some nori to the side of the tank, they really liked that. I have to put two pieces in there cause they try to eat the same piece and keep poking each other. One of them always grabs my thermometer and cruises around with it all day.....they are really fun to watch! Maybe you will want to try a smaller one in the future.

 

[quarryshark]

Ya mine like the nori clip too.
He wouldn't give it back for a week.