Things that eat Coralline algae

ajmckay

Soooooo.... I've had a long-spine urchin in my tank for a few months.

He typically just hung out in a cave on the back of a rock and I hardly ever saw him move. I could see his spines sticking out so it was cool though. Well over the past 2 weeks or so he's been out almost constantly... He moves all over the place and really it's kind of cool to see him fit into cracks you would never think he could fit into due to his spines sticking out in all directions. Well, my concern is that he's recently developed a taste for coralline algae, and he's pretty handy at dispatching colonies of it.

The trouble is that I really like my coralline algae, and it's beginning to really take hold in my tank. Sometimes he just leaves these little white X-shaped bite marks all over, but other times the entire "crust" of coralline is gone down to bare rock...
Well, to get to the point, I like the algae, and I like the urchin too....

So my question is: What do you do to get coralline algae to grow faster?
I don't really have much for other types of algae (I don't know if that's a good thing, or a bad thing...) in the tank. I've heard "purple up" is a good product?

I would appreciate any suggestions if you have experience caring for a longspine urchin!

onefish2fish

if you had a sump you could temp. house the urchin in there.

i dont know if theres much to can do to increase coraline growth. i know scraping alittle off the glass will release spores and theres a product called "purple up" but IMHO i think that is just over priced alk supplement.

wish i had better advice but it seems like its going to be one or the other.

Cody

This is the downfall of Urchins. They all eat coraline.

The best way to get your coraline back is to use some Kalkwasser or PurpleUp. Can't help you on anything else unless you get rid of the Urchin.

CathyJ

Purple up and keeping your calcium up to 400/425 will help with the coraline growth.

But the urchin can easily out grow your tank. They can get pretty big. In a large tank, with lots of live rock you can keep an urchin and coraline, but in a 29, you will pretty much have one or the other.

ajmckay

Thanks for the advice... This is a 29 gallon tank, and for now I don't have a sump (and probably won't for a year or so until I can decide on a tank upgrade which I will have to drill or get pre-drilled). I do, however, like the idea of putting him in a sump... What about a HOB refugium? I've been thinking about building a 24" x 4" x 12" HOB refugium, do you think that might be enough space to keep the guy happy for a week or 2 while the algae recovers? What I would optimally want is a quantity of coralline that would replenish itself faster than the urchin can eat it... I mean I don't mind the urchin narshing it, he's just eating it faster than I thought he would, and faster than the tank is producing it at the moment...

I think I might try some supplements just as an experiment and track things closely. Also, does anyone know of a way to feed urchins and keep them happy thus reducing their grazing behavior slightly?

To be clear I knew he would probably eat the coralline, I'm just surprised at how fast it does! And he's still just a little guy at 2.5 inches wide!!

onefish2fish

a HOB fuge wont be large enough to substain his appitite, and im not sure what you can suppliment withthe urchins diet, if anything.

onefish2fish

idk if it will eat nori ( i think its called nori ) but its algae sheets. im not 100% but maybe someone here can clarify

ajmckay

Onefish... good idea... I'll see if I can get it to possibly eat nori... I have some of that actually that I've fed before and the hermits go crazy for it...

karaim

I have 3 urchins (2 pencil urchins and 1 pincushion urchin). They all eat Nori (purple or green). Just as a note of caution, the urchnis will also eat featherdusters. I learned the hardway - without researching compatability. Came home one day and found half of the featherduster inside the urchin's moth

ajmckay

Thats great to hear that they eat the nori!

I've put some into the tank, but my hermits hoarded it... I suppose I might need to take a more targeted approach and somehow attach the nori to a rock or to the glass closer to the urchin. I'll try it as soon as I return from vacation! Thanks for the input. BTW, what size tank do you have? And what kind of feather duster did he eat? I don't think he would eat my FD because he is super skiddish... Slightest shadow/bump/noise and he retracts... I suppose he could be narshing some of the small ones... but I've got tons of those so thats okay...