Sea urchins are beautiful creatures that can come in many sizes and colours, they have an amazing spiny defence system that no predator would dare to come into conflict with.

Most urchins such as the pincushion are not venomous but there are certainly others out there that have taken the spines a step further.

Some urchins have hollow spines that will dig into and snap off in the flesh of their would be predator, some have a bag of venom at the top of each spine ready to release a toxin as it penetrates the flesh.

The only venomous urchin that we tend to keep here at Water Decor is the long spined black urchin, it has a very mild venom and it’s sting is comparable to that of a wasp sting.

The mouth of the urchin is located at the bottom or underside of it’s body, it contains 5 sharp teeth that are perfectly placed for grazing the aquarium rocks and glass. Urchins are primarily herbivorous but will often take meaty foods like krill, mysis, clam meat etc.

The main bulk of their diet is filamentous and coralline algae, these must be in a plentiful supply to sustain the grazing habits of the urchin. The main cause of death to urchins in the home aquarium are malnutrition and water quality changes, every effort should be made to acclimatize the specimen slowly to prevent shock.

All of the sea urchins listed below are regularly available here at Water Decor, others are available to order.

Longspine Black Urchin (Diadema setosum) Care Level: Easy. Lighting: T8, T5 or Metal Halide. Feeding: Grazes on algae, suppliment feeding with dried algae & seaweed. Temp: 26°C SG 1.023-1.025. Max. Size In Aquarium: Up to 10” . Temperament: Peaceful. Colour: Black. Reef Compatible: Yes. Origin: Caribbean, Indo-Pacific. Additional Information: Mildly Venomous	Tuxedo Urchin (Mespilia globulus) Care Level: Easy Lighting: T8, T5 or Metal Halide Feeding: Grazes on algae, suppliment feeding with dried algae & seaweed. Temp: 26°C SG 1.023-1.025 Max. Size In Aquarium: Up to 3" Temperament: Peaceful Colour: Blue, Red, Black Reef Compatible: Yes Origin: Indo-Pacific.
Pincushion Urchin (Lytechinus vaniegatus) Care Level: Peaceful. Lighting: T8, T5 or Metal Halide. Feeding: Grazes on algae, suppliment feeding with dried algae & seaweed. Temp: 26°C SG 1.023-1.025. Max. Size In Aquarium: 8". Temperament: Peaceful. Colour: White, Blue, Purple, Red. Reef Compatible: Yes. Origin: Caribbean, Atlantic.	Pencil Urchin (Eucidaris tribuloides) Care Level: Moderate. Lighting: T8, T5 or Metal Halide. Feeding: Grazes on algae, suppliment feeding with dried algae & seaweed. Temp: 26°C SG 1.023-1.025. Max. Size In Aquarium: Up to 6". Temperament: Peaceful. Colour: Red, Brown, Black. Reef Compatible: Yes. Origin: Caribbean, Philippines.