Overview
The Pencil Urchin (Eucidaris tribuloides) is a intermediate saltwater species known for its brown-red, thick blunt spines coloration. Thick blunt spines. Surfaces.
Origin & Appearance
Origin: Caribbean.
Colors: Brown-Red, Thick blunt spines.
Body Shape: Urchin (spherical/spiny). Typical adult dimensions: 12.0 x 12.0 x 8.4.
Sexual Dimorphism: Minimal.
Tank & Water Requirements
| Min Tank Size | 30 gallons |
| Temperature | 75–81°F |
| pH Range | 8.1–8.4 |
| Water Hardness (GH) | dKH 8-12 |
| Bioload | low |
| Oxygen Demand | medium |
| Plant Safe | yes |
| Aquarium Position | Surfaces |
Behavior & Activity
Slow reef grazer; thick blunt spines sway during movement; tube feet create steady crawling; coralline algae eater
Speed: 15/100Aggression: 1/10diurnal
Breeding
Not bred at home; broadcast spawner
Common Diseases
💊 Sensitive to salinity💊 copper
Expert Notes
Thick blunt spines; may eat coralline algae