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Longspine Urchin, Black
Please Note: Due to variations within species, your item may not look identical to the image provided. Approximate size range may also vary between individual specimen.
Longspine Urchin, Black (Diadema setosum)
Additional locales and sizes may be available!

Quick Stats

Care Level Easy
Temperament Peaceful
Color Form Black, Blue, Green, White
Diet Herbivore
Reef Compatible Yes
Water Conditions 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025
Max. Size 10"
Venomous Yes
Origin Caribbean, Fiji, Indonesia
Family Diadematidae
Supplements Calcium, Iodine, Trace Elements
Compatibility View Chart
What do these Quick Stats mean? Click here for more information


The Black Longspine Urchin, also known as Long-spined Sea Urchin, has a body which is predominately black with a red eyespot in the center. The spines on these urchins are long, thin and completely black. They are a very delicate looking urchin, which are actually very capable of protecting itself. These urchins are excellent algae controllers for an aquarium housing aggressive fish.

Provide an aquarium with ample hiding places and room to roam. Being a nocturnal creature, the Black Longspine Urchin will hide during the day and only come out at night to forage for food such as algae and seaweed. These urchins are an excellent algae controller for an aggressive aquarium where other invertebrates would be eaten. When approached by a fish, these urchins will sense their presence, and will defend itself by directing its spines towards its offender.

It is very sensitive to high levels of copper-based medications and will not tolerate high nitrate levels. If it begins to shed its spines, it is a sign of very poor water quality.

Be aware, it is venomous, with its sting being roughly equivalent to that of a bee sting.

The diet may be supplemented with dried seaweed.

Approximate Purchase Size: Small: 1-1/2" to 2"; Medium: 2" to 3" Large: 3" to 4"

Customer Testimonials

Mason H Chappaqua , NY
It's surprising how one of these catches your eye in the aquarium. Especially with the cool tube on the top of it.
Ken T Forest Grove , OR
Do not put in with bubble corals; it destroyed mine by puncturing its bubbles. By the time I got it into another tank the bubble coral only had about 1/3rd of itself left.
David A Colton , NY
Just received my first Longspine Urchin. Great little creature, very active, and appears to be very healthy. Very different.
Ben D Mooresville , NC
They are cool to watch, but when you clean the tank, watch your hand.
Jake Chicago , IL
I would not call these reef safe at all.... they are great with algae control, but once it's, gone they will go for the corals.
Elizabeth W Panama City Beach , FL
Long this guy, I saw where many said they wouldn't put them with some coral and I have lots of coral and he doesn't truth it at all. I have had mine about two months and he has doubled in size.
Suzanne A Joplin , MO
My urchin is the hardiest specimin in my 30 gallon tank. Even when compared to fish. He is not sensitive to poor water parameters, and he roams day and night. He has about tripled in 2 years. I wouldn't call him reef safe though since he ate 2 of my ricordea polyps.
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