Urchins and Coralline

[KariE2B]

Ok, so I have a bunch of urchins in my tank...I have been told before that they eat coralline..has everyone had the same experience...if they all eat coralline, why would anyone want them in their tank? I just put them in a little tank so I can give them to a pet store tomorrow..but, I have kinda grown attached to the little buggers.

[Jim J]

I have kept urchins in both reef and FO tanks. They do help keep all types of algae on rocks to a minimum, but they seem to do so by removing the surface of the rock. I could always see the trail they left by the freshly exposed surface on the rock. Any desirable coraline that had been on the rock was gone.

 

I understand your affliction...I mean affection...towards your urchins, as I had a very hard time getting rid of mine. Maybe you would consider setting up a tank just for them, and not worry about maintaining any coraline algea.

 

Some types of urchins (long spine) can be very hazardous to corals (and the keeper) due to the sharpness of the spines.

 

I had several species of urchins, but would only keep pencil urchins in my reef tank because of their blunt tipped spines. The urchins would become covered with coraline, too. But still they left areas of freshly exposed rock wherever the stopped to graze.

 

I think urchins are cool to keep, as long as you understand their needs. However I would hesitate to call them reef safe.

[Aiptasia]

Just like Jim, I had a few long spined ones spring up out of some LR on a 55g. reef I used to have. They do pretty much scrape away the entire surface of the LR as they move along, like a tornado carving a furrow through a field as it strips the surface clean. Good algae, bad algae, it's all the same to them.

 

You can pluck them out of the tank with long handled tweezers or hemostats, but be careful not to squish them. Abalone divers in California used to kill them off because they would eat the holdfasts on Macrosystus porifera (giant kelp) and ruin abalone beds. The problem was, if you squish them or knife them, they will release their gametes, so the result was an explosion of new baby urchins and much more rapid depletion of the kelp beds.

 

Long spined ones can be toxic, and they aren't reef safe, but they are extremely cool to watch. If you want to keep them, by all means do so in a tank with lots of LR for them to graze, but you should probably get them out of the reef tank.

[MillerLite]

"Affliction...affection"...LOL. I too suffered the "how cool are they" syndrome when I first started up my 55 gallon. I had a black urchin and a blue tuxedo urchin . The blue tuxedo urchin was cool as hell, picking things up to camoflauge itself. However, soon learned that they can easily rearrange rock and decimate any soft and encrusted algaie (ie.corraline) that was on the rock...in a matter of a few months. It seemed the the black urchin even preferred the encrusted stuff to the soft...my 2 cents.