I've had this Urchin for 2 years and he's the best urchin ever. But I forgot what kind he is

[Subnautica]

Over the years I've had quite a few urchins. 3 Tuxedos, 2 Pincushions, etc... But all of them couldn't survive more than a year except this guy. The thing is, 99% of the time he always stays on the glass and NEVER bothers any coral frags or knock them out, unlike the pincushion and tuxedo which was super annoying to me. I was curious why this guy is different/has such "good manner" ?

Also he looks like a longspine but I think they look a bit different? What kind is this guy?

2inch in diameter

 

[MERKEY]

Looks kind of like a pencil urchin.

 

[ISpeakForTheSeas]

Probably a Burrowing Urchin, Echinometra mathaei:

Black/Oblong Rock-boring Urchin - Echinometra oblonga; it could also be the Burrowing Urchin, E. mathaei, as the two are similar enough that E. oblonga was once considered a morph of E. mathaei,* but - based on the coloration of your specimen - E. oblonga seems more likely to me.

Either way, both species primarily reside in the rocks and primarily feed on turf algae of various kinds** - so a good herbivore for your tank.

*Source:

Echinometra oblonga - Plazi TreatmentBank

treatment.plazi.org

**Source:

https://www.ingentaconnect.com/contentone/umrsmas/bullmar/2007/00000081/00000001/art00006?crawler=true

An easy way to distinguish adult P. gratiosa from adults of Echinometra species like E. mathaei or E. oblonga is size: if the urchin is bigger than ~3.5cm, it's an Echinometra. The other easy way to distinguish is by looking at the periproct plates (the "teeth" around the urchin's anus); P. gratiosa will only have 3-5 periproct plates while an Echinometra species will have a bunch (for examples, see the links below; the second pic of the Lizard Island Guide shows P. gratiosa's periproct plates, and figure 8 from the Semantic Scholar link shows the periproct of E. mathaei - it's a lot harder to see the periproct of E. mathaei clearly on live specimens, but they also have a pic of the area in figure 1). The French Wikipedia page lists some more subtle differences, but the methods above would be my suggestion for differentiating them.
species: Parasalenia gratiosa in taxonomy (Lizard Island Field Guide) https://www.semanticscholar.org/paper/Description-on-anatomy-and-histology-of-Echinometra-Piryaei-Mostafavi/a4efce70d6fcd0cc081b552033101ca768d9552f Edit: Forgot to add the French Wikipedia link:

Parasalenia gratiosa — Wikipédia

fr.wikipedia.org

All that said, Echinometra species are reportedly much more common, so I'd assume that's what you have.

 

[vetteguy53081]

Over the years I've had quite a few urchins. 3 Tuxedos, 2 Pincushions, etc... But all of them couldn't survive more than a year except this guy. The thing is, 99% of the time he always stays on the glass and NEVER bothers any coral frags or knock them out, unlike the pincushion and tuxedo which was super annoying to me. I was curious why this guy is different/has such "good manner" ?

Also he looks like a longspine but I think they look a bit different? What kind is this guy?

2inch in diameter

Pencil urchin and funny is ive had mine also 2 years. Drags Nothing around

 

[Fishy888]

Pencil urchin and funny is ive had mine also 2 years. Drags Nothing around

Don’t they eat coral?

 

[ISpeakForTheSeas]

Don’t they eat coral?

The pencil urchin Eucidaris tribuloides (the most common "pencil urchin" in the hobby) does, yes (at least when they don't have access to sponges).

 

[Fishy888]

The pencil urchin Eucidaris tribuloides (the most common "pencil urchin" in the hobby) does, yes (at least when they don't have access to sponges).

I thought I read that. As I’m trying to grow both corals and cryptic sponges, I won’t be getting any pencil urchins, even though they look cool.

 

[Subnautica]

The pencil urchin Eucidaris tribuloides (the most common "pencil urchin" in the hobby) does, yes (at least when they don't have access to sponges).

Hmm thats weird because mine ever ate coral at all

 

[ISpeakForTheSeas]

Hmm thats weird because mine ever ate coral at all

If you had E. tribuloides and it didn't eat corals, then it had something it preferred over them in the tank (it's reportedly spongivorous in the wild, so some sponges would be its top preference, but they'll eat literally just about anything if they're hungry enough):

What type of Eucidaris? Sold as Pencil Urchin

Curious if anyone knows the species of this pencil urchin? I mostly want to confirm/deny if it’s a known coral or clam eater?

www.reef2reef.com

To clarify again here though, your urchin in the pics of this thread is not a pencil urchin - it's most likely Echinometra mathaei, which is herbivorous.

 

[vetteguy53081]

Don’t they eat coral?

I have ton of coral and it has never touched one

 

[UMALUM]

Pencil urchin

 

[Subnautica]

If you had E. tribuloides and it didn't eat corals, then it had something it preferred over them in the tank (it's reportedly spongivorous in the wild, so some sponges would be its top preference, but they'll eat literally just about anything if they're hungry enough):

What type of Eucidaris? Sold as Pencil Urchin

Curious if anyone knows the species of this pencil urchin? I mostly want to confirm/deny if it’s a known coral or clam eater?

www.reef2reef.com

To clarify again here though, your urchin in the pics of this thread is not a pencil urchin - it's most likely Echinometra mathaei, which is herbivorous.

Yeah he def doesn't look like a Pencil urchin to me. He'a closer to Mathaei even though still a little bit different I think.

 

[Borat]

Nice sea hedgehog!

 

[MDReefguy]

I always referred to mine as a short spine urchin. I have what looks like the exact same one.

Shortspine Urchin (Echinometra sp.) Atlantic - Clean Up Crew

Shop The Best Saltwater Aquarium Equipment & Supplies at Saltwater Aquarium. We Carry Everything you will Need for your Fish Tank.

www.saltwateraquarium.com

 

[jabberwock]

My purple spine urchin's spines got progressively shorter over the past year. He cam in TBS Ocean live rock. I think he is adapting to tank life by letting his spines get scraped shorter.

Early on

And now

It looks like he might be left handed...

 

[SirenBethany]

Over the years I've had quite a few urchins. 3 Tuxedos, 2 Pincushions, etc... But all of them couldn't survive more than a year except this guy. The thing is, 99% of the time he always stays on the glass and NEVER bothers any coral frags or knock them out, unlike the pincushion and tuxedo which was super annoying to me. I was curious why this guy is different/has such "good manner" ?

Also he looks like a longspine but I think they look a bit different? What kind is this guy?

2inch in diameter

It's a purple short spine Urchin, some call them red urchins as individual colors can vary

 

[mdpitts]

I have ton of coral and it has never touched one

Tank goals...

 

[vetteguy53081]

It's a purple short spine Urchin, some call them red urchins as individual colors can vary

Looks like pin cushion

 

[Paul B]

It's not a long spine. This is a long spine.



It looks more like a purple urchin that I used to collect here in New York by the dozens.
But I can't tell from here.




I used to have an urchin collecting business and would take 50 on every dive. They are very common.