so far so good: sea urchin eats caulerpa

[Sk8r]

Tripneustes gratilla [the hairy pincushion urchin: red/white] from LiveAquaria.com shows initial promise as a non-destructive cleaner in an sps tank. It's so far worked around the corals and nibbled on caulerpa, as advertised.

I was a bit dismayed by the size: doorknob sized, in my little 52g, when I'd rather hoped for a one-incher, but so far it shows the grace of a balletic elephant in a china shop, missing every opportunity to knock things off.

It shows some disposition to linger over the bubble algae: I can only hope. Definitely it eats caulerpa and that rock-covering red algae. It may give an easier time to my encrusting coralline, which doesn't make great progress against that red stuff.

Because my rocks are not smooth, it can't strip them, for good or for ill.

He's an unexpectedly handsome specimen: striking color, white and rust-red, and a heck of a lot easier to catch than a rabbit fish if he proves too rowdy.

 

[Sk8r]

Day 2: I can report this creature is doing very nicely, has behaved impeccably with the corals, and is very fond of grape caulerpa, the bane of my tank. He doesn't travel much, having a lot to do with one rock, but he's eating the whole time.

 

[Sk8r]

After 1 week with the creature, I can report no damage. He's fist-sized, and I've had to move a couple of corals to give him access to a problem area, but in general he can glide along a narrow rock edge between a bali slimer and a foliosa, suspending his main body via his gripping feet, damaging neither, though he was totally overhanging the foliosa. He hasn't knocked anything off, he's been very busy, and generally when he gets to a caulerpa patch, he uses his sucker feet to haul on the caulerpa vines until he can nosh them.

A very model citizen, so far.

 

[RCMark325]

Thanks for posting... I just ordered my urchin off liveaquaria.com too! Does yours eat any filament algae like green hair or that pink fuzz?

 

[Sk8r]

I don't have any of that: I do have the red algae, and he deals with that bigtime. Where he passes, the rock is bare. He's noshed on coralline a bit, but only on the surface, and occasionally he gets up and cleans the glass---not often, though: he's a rock critter, hates the sand, and the way he can get that 3 inch wide body past corals that I swear are closer than that is really amazing. He won't stay at any one type of algae too long, but he cycles back to a grazing spot. I kind of suspect he lays a scent trail or something to enable him to find the easy path. So far no damage at all from him. I did have to glue one frag that had been 'set-in' but it's my fault, not his. And he didn't knock it off, only nudged it askew.

He's annoyed a few of my snails and hermits by picking them up and putting them on his butt until they fall off, but he still hasn't hurt them.