Local Fish Store sold me "Spiny Urchins," what species is this?

[Trenox]

Hey all, created an account just to ask this.

A few weeks ago I bought some urchins from my local fish store; The owner referred to them as "Spiny Urchins" informally, with the actual label on the tank being "Long-Spine Urchins (Diadema spp.)." They had red and greenish-black color variations (or different species in the same genus?) available, and I got one of each. Here they are:



However, upon looking up the long-spine urchin, no other Diadema urchins seem to look anything like mine. Looking at other websites advertising Diadema species for sale, they all note the urchins' bright periproctal cone and very long, thin spines, with all the pictures showing the urchin being a very dark, mostly uniform color (with some having banded spines). My urchins have much broader, stockier spines, are more colorful overall (additionally having a lighter base on each spine, and a darker tip, rather than the uniform or banded look), and most notably, completely lack the definitive bright coloration on the periproct that all Diadema species seem to share. They look a lot more similar to the Rock-Boring Urchin, but the color is still totally different from those, and I haven't seen them boring into any rocks.

Does anyone know what species of Urchin this is specifically?

 

[CocoReef]

First welcome to r2r! It looks like they are part of the echinometra family but Im not positive. Hopefully someone can help you get a definitive answer though

 

[vetteguy53081]

Pencil urchin. . . . Many call them spiny urchin

 

[Garf]

Hey all, created an account just to ask this.

A few weeks ago I bought some urchins from my local fish store; The owner referred to them as "Spiny Urchins" informally, with the actual label on the tank being "Long-Spine Urchins (Diadema spp.)." They had red and greenish-black color variations (or different species in the same genus?) available, and I got one of each. Here they are:



However, upon looking up the long-spine urchin, no other Diadema urchins seem to look anything like mine. Looking at other websites advertising Diadema species for sale, they all note the urchins' bright periproctal cone and very long, thin spines, with all the pictures showing the urchin being a very dark, mostly uniform color (with some having banded spines). My urchins have much broader, stockier spines, are more colorful overall (additionally having a lighter base on each spine, and a darker tip, rather than the uniform or banded look), and most notably, completely lack the definitive bright coloration on the periproct that all Diadema species seem to share. They look a lot more similar to the Rock-Boring Urchin, but the color is still totally different from those, and I haven't seen them boring into any rocks.

Does anyone know what species of Urchin this is specifically?

You got anything for them to eat? Your rock looks very clean.

 

[blaxsun]

Definitely pencil urchins (and nice ones). Get those guys some seaweed!

 

[Rmckoy]

Pencil urchin. . . . Many call them spiny urchin

I always thought pencil urchins had more of a blunt quill ?

 

[vetteguy53081]

I always thought pencil urchins had more of a blunt quill ?

Thats the way they sell them. Here is a pic of healthy ones. Looks very close to short spined urchin. I hate to debate with myself

 

[Rmckoy]

Thats the way they sell them. Here is a pic of healthy ones. Looks very close to short spined urchin. I hate to debate with myself

I’m not debating at all .
I had one that was very blunt .
but in the lfs today they had blunt ones labeled pencil urchins .
and ones like the picture above labels spiny urchin .
along with a few long spine in the same display .

 

[Trenox]

You got anything for them to eat? Your rock looks very clean.

They've done a good job cleaning that little area off. Whenever they clean the rocks and are still hungry, they go down to the floor and leave white trials on the substrate. I was going to buy some sinking algae wafers for them if the clean up crew was eating more than could regrow, but it's a 90 gallon tank and they're small so there's plenty growing for them as it is.

Definitely pencil urchins (and nice ones). Get those guys some seaweed!

I'll pick up some nori or something similar for them. Thanks for the suggestion.

First welcome to r2r! It looks like they are part of the echinometra family but Im not positive. Hopefully someone can help you get a definitive answer though

Thanks. I think you're correct, looking through the different species, Echinometra Viridis, the reef urchin, looks pretty much identical:

 

[Miami Reef]

Apparently pencil urchins aren’t reef safe?

 

[DaJMasta]

Doesn't look like any of the pencil urchins I've seen... those look like Echinometra virides, as said before.

I've got one and it's just fine, doesn't eat coral nor pick things up.

 

[Steve and his Animals]

Apparently pencil urchins aren’t reef safe?

I hear that a lot. I imagine it's more an issue of feeding. Urchins eat all day, so I wouldn't be surprised if they ate coral when they were desperate. I've had customers bring back longspines for doing the same thing. They're usually big by that point, which to me either says a lack of regular food or possibly a shift in diet with age, possibly like what a lot of cowries go through.