Description
Purple Stripe Sea Urchin – Asthenosoma varium
(Common name: Fire Urchin)
Overview:
The Purple Stripe (Fire) Urchin is one of the most striking but also dangerous urchins in the aquarium trade. It has a rounded body covered with vibrant red, orange, and purple spines arranged in radiating stripes. Unlike most common urchins, its spines are venomous, capable of causing very painful stings. Because of this, it is best suited only for advanced aquarists.
Origin:
Found across the Indo-Pacific region, particularly around reefs, lagoons, and sandy bottoms.
Feeding:
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Omnivorous grazer.
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Eats algae, detritus, and sometimes sessile invertebrates.
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In captivity, can be offered nori (dried seaweed), spirulina, and small meaty foods.
Tank Mates:
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Reef caution: May harm corals and sessile invertebrates while grazing.
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Must not be housed with fish or invertebrates that nip at spines.
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Safe with most peaceful reef fish if left undisturbed.
Aggression Level:
Peaceful, but extremely dangerous to humans if handled—spines contain venom and can inflict a painful sting.
Experience Level:
Advanced. Requires careful handling (preferably none at all) and a mature, well-fed tank.
Water Parameters:
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Temperature: 74–80°F (23–27°C)
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pH: 8.1–8.4
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Salinity: 1.023–1.025
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Tank Size: 75+ gallons
Unique Features:
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Brilliant red/orange body with purple bands/stripes.
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Venomous spines capable of painful stings that can cause swelling and numbness.
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Unlike many urchins, it has pedicellariae (tiny pincer-like structures) between spines that can also inject venom.
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Sometimes symbiotic with small shrimps or crabs that hide among its spines for protection.
✨ The Purple Stripe (Fire) Urchin is spectacular but risky—its stunning colors make it a showpiece, but its venomous spines make it suitable only for expert aquarists who can provide a safe, stable reef system.
