Urchin ID

[wanderer]

I wonder if anyone could ID this urchin. I previously had a single blue tuxedo and since I have a ton of hair algae I wanted to get a second one to help clean up the tank. LFS owner insisted this was a red tuxedo. Any idea what this is and also what it eats? If it eats algae and not coral I don’t mind keeping it. It’s a little under 2 inches in diameter, spines are not sharp or painful to handle. It doesn’t wear things for camouflage and I can’t tell if it’s eating algae but it is fairly active both day and night

Google AI suggests Salmacis bicolor but I’ve never seen that listed for sale anywhere

 

[kevgib67]

Ya, doesn’t look close. Very beautiful though and I’m sure does what urchins do. Let’s see if we can get a id. @ISpeakForTheSeas , @WheatToast

 

[ReeferHD]

looks like a

Red Bell's Urchin - Salmacis belli​

 

[shcrimps]

woah that’s a cool urchin

 

[kevgib67]

Never heard or seen one but now I need one!!!!!!

 

[resortez]

I second the man with the clam

looks like a

Red Bell's Urchin - Salmacis belli​

 

[ISpeakForTheSeas]

looks like a

Yeah, definitely a Salmacis species - I'm not sure which one, as S. belli, S. bicolor, and S. erythracis all look very similar. I can't find a whole lot about their diets, but S. sphaeroides is noted as being a primarily herbivorous omnivore (it's noted as occasionally eating other urchins - including other Salmacis urchins - sea pens, plants, jellyfish, and algae).* I've heard some species (probably all/most) need lots of calcium, so they may (will) eat coralline algae, or you can sometimes offer them things like cuttlebones to try and prevent them from eating coralline off of your rocks.**

*Sources:

https://www.researchgate.net/publication/240821453_Feeding_behavior_of_the_urchin-eating_urchin_Salmacis_sphaeroides

https://www.sciencedirect.com/science/article/abs/pii/030437709390022O

https://onlinelibrary.wiley.com/doi/abs/10.1111/are.12128

**Source:

Section: Urchins: Group: Common Urchins: Species: Salmacis belli (Pin Urchin)

Marine Aquarium Library: Common Urchins, Order: Temnopleuroida - Family Temnopleuridae, Salmacis belli

www.saltcorner.com

 

[wanderer]

Thanks for all the responses. I’ve had it for a few days now and I don’t see it eating any of the algae though it’s hard to be certain. I did see it on top of a zoa and I’m worried that it may be corallivorous. I will probably have to rehome it

 

[ISpeakForTheSeas]

Thanks for all the responses. I’ve had it for a few days now and I don’t see it eating any of the algae though it’s hard to be certain. I did see it on top of a zoa and I’m worried that it may be corallivorous. I will probably have to rehome it

Let us know if you see it actually eat any/leave a noticeable path of eaten coral - that would be some good data to have for any future users who get one of these.

 

[kevgib67]

^ This, I was actually thinking of tracking one down but I think I’ll wait and see how yours works out.

 

[wanderer]

Let us know if you see it actually eat any/leave a noticeable path of eaten coral - that would be some good data to have for any future users who get one of these.

I’ll check to see if the polyp opens up. Unfortunately I have a newish tank that has been overrun with algae and only just started putting corals in and don’t have much to test. I moved it to a wall full of gha and will see if it eats that. I also have small chaeoto in my sump I can try to feed it

 

[wanderer]

on further observation it does seem to be eating algae. It has spent the last day going in circles around my mp40. I just noticed the mp40 is cleaner than it has ever been. I attached a pic of the other mp40 for comparison.

The 2 different zoas I found it on are still alive so it’s possible it was eating the algae around the zoas but impossible to know for sure. But at the very least it’s at least partially herbivorous

 

[wanderer]

It seems to have left my corals alone so I’m guessing it was probably eating the algae around the corals.

It has been a few week and my corals are doing okay so I would say that this is most likely reef safe

 

[ISpeakForTheSeas]

It seems to have left my corals alone so I’m guessing it was probably eating the algae around the corals.

It has been a few week and my corals are doing okay so I would say that this is most likely reef safe

Thanks for the update! Please let us know if that changes at some point in the future.

 

[wanderer]

Thanks for the update! Please let us know if that changes at some point in the future.

Unfortunately the urchin died last week. My GHA has mostly disappeared in the last couple months and perhaps it ran out of food ?

I have two tuxedos that are still doing well. Besides a tiny amount of GHA I have what looks like Cyano as well as film algae and they must be eating that.

It’s also possible that it needs additional food supply that is not easily supplied in a tank and I would not buy this again for this reason

@ISpeakForTheSeas @kevgib67

 

[kevgib67]

Unfortunately the urchin died last week. My GHA has mostly disappeared in the last couple months and perhaps it ran out of food ?

I have two tuxedos that are still doing well. Besides a tiny amount of GHA I have what looks like Cyano as well as film algae and they must be eating that.

It’s also possible that it needs additional food supply that is not easily supplied in a tank and I would not buy this again for this reason

@ISpeakForTheSeas @kevgib67

Sorry to hear about your urchin! What size tank do you have? I have multiple times in the past, rubber banded nori to a rock when I’ve noticed minimal algae in my tank and also algae wafers for my other herbivore inverts.

 

[wanderer]

Sorry to hear about your urchin! What size tank do you have? I have multiple times in the past, rubber banded nori to a rock when I’ve noticed minimal algae in my tank and also algae wafers for my other herbivore inverts.

It’s an 80 gallon. I’ll definitely keep that in mind with regard to the nori and algae wafers

 

[ISpeakForTheSeas]

Unfortunately the urchin died last week. My GHA has mostly disappeared in the last couple months and perhaps it ran out of food ?

I have two tuxedos that are still doing well. Besides a tiny amount of GHA I have what looks like Cyano as well as film algae and they must be eating that.

It’s also possible that it needs additional food supply that is not easily supplied in a tank and I would not buy this again for this reason

@ISpeakForTheSeas @kevgib67

Sorry for the loss, but thank you for the update - this is good info to start with.

 

[kevgib67]

It’s an 80 gallon. I’ll definitely keep that in mind with regard to the nori and algae wafers

Ok, 3 in a 80 gallon should be fine but when there is little algae I would recommend supplementing. I know it’s a tough problem to have, not having a lot of hair algae all over your tank !