Multicolour Halloween Urchin
Multicolour Halloween Urchin
Species: Multicolour Halloween Urchin (Tripneustes gratilla)
Growth Form: Marine echinoderm (urchin)
Coloration: Bright orange, black, and purple banded spines
Temperament: Peaceful
Tank Size: 30+ gallons
Placement: Rockwork, glass, and substrate
Lighting: Moderate to high
Flow: Moderate
Diet: Herbivore (algae, film algae, coralline)
Feeding: Supplement with nori or algae wafers if natural algae is limited
Reef Safe: With caution (may knock over loose frags, may graze coralline)
Care Level: Easy to Moderate
Multicolour Halloween Urchin
Available for local pickup and shipping
Common Names:
Multicolour Halloween Urchin
Halloween Urchin
Tripneustes gratilla
Identification
The Multicolour Halloween Urchin is a striking and unique echinoderm known for its vibrant coloration and rounded body shape. It features a combination of bright orange, black, and sometimes purple banding across its spines, giving it a bold “Halloween” appearance. Its short, dense spines and visible tube feet allow it to move efficiently across rockwork and substrate.
Size:
Typically grows up to 3–4 inches (7–10 cm) in diameter.
Behavior & Role in a Reef Tank
Temperament:
Peaceful and non-aggressive; does not bother fish or most invertebrates.
Habitat:
Active grazer that constantly moves across rockwork and glass surfaces. May carry small debris, shells, or frags on its back as camouflage.
Diet:
Primarily herbivorous—feeds on algae, including film algae and some nuisance algae. Will also consume coralline algae if food is limited.
Compatibility & Caution
Reef-Safe:
Generally reef-safe with caution—safe with corals but may dislodge loose frags while moving.
Algae Control:
Excellent member of a clean-up crew for controlling algae growth.
Caution:
Can knock over unsecured corals and decorations. May graze on coralline algae. Ensure stable rockwork and securely placed frags.
Care Level
Difficulty:
Easy to Moderate—suitable for most reef aquarists.
Water Conditions:
Stable reef parameters required:
Temperature: 72–78°F (22–26°C)
Specific Gravity: 1.023–1.025
pH: 8.1–8.4
Diet:
Primarily algae-based diet. Supplement with dried seaweed (nori) or algae wafers if natural algae is insufficient.
Tank Mates
Compatible with most peaceful reef fish and invertebrates.
Avoid predators such as triggerfish, large wrasses, and puffers that may nip at or prey on urchins.
Fun Fact
Halloween Urchins are known for their quirky habit of “decorating” themselves—using their tube feet to pick up shells, rubble, or even coral frags to place on their backs as protection from light and predators!