Pincushion Urchin Care Guide
Tripneustes gratilla, the collector or pincushion urchin, is an Indo-Pacific algae grazer with dense short spines that often collects debris on its body.
Overview
Tripneustes gratilla, the collector or pincushion urchin, is an echinoid of the family Toxopneustidae from the Indo-Pacific. The domed test bears dense short spines, often white over a bluish-purple body or with orange tips, and the animal characteristically piles debris, shell and algae on itself for camouflage. It is a continual algae and seagrass grazer.
Taxonomy
- Class: Echinoidea
- Order: Camarodonta
- Family: Toxopneustidae
- Genus: Tripneustes
- Scientific name: Tripneustes gratilla (Linnaeus, 1758)
Habitat
The species occurs across the Indo-Pacific including Hawaii, the Red Sea and the Bahamas, ranging from Mozambique to Hawaii and the Tuamotus. It inhabits depths of about 2–30 m; adults favour open bottoms with some shelter while juveniles hide among rocks. Adults reach about 10–15 cm.
Tank requirements
- Minimum tank volume: 150 L
- Temperature: 24–26 °C (75–79 °F)
- pH: 8.1–8.4
- Carbonate hardness (dKH): 8–11
- Specific gravity: 1.024–1.026
- Adult diameter: about 10–15 cm
- Lifespan: roughly 3–5 years
A medium to large tank with open rockwork and stable parameters suits it; because it grazes constantly, supplement with dried algae sheets when natural growth runs low.
Diet
Tripneustes gratilla grazes day and night on algae, periphyton and seagrass, and in some habitats consumes a substantial share of seagrass production. In the aquarium it works as a voracious algae grazer.
Compatibility
It is reef compatible as a grazer; the short spines pose less risk to corals than the long-spined Diadema, though it may bulldoze loose frags and decor. Avoid urchin predators such as triggerfish and pufferfish.
Conservation status
Overexploitation, partly for its edible roe, has driven sharp declines in collector urchin populations in some exploited regions.