Shortspine Urchin

Species/Animal: (Invertebrates) Shortspine Urchin (Echinometra sp.)

Description:
The Shortspine Urchin is a peaceful species that is generally considered reef-safe with caution, admired for its compact round body, relatively short spines, and ability to graze on algae and detritus. Unlike long-spined urchins, it has sturdier, shorter spines, making it easier to keep in community aquariums. Its colors can range from purple to pink, brown, or reddish tones, often with banding or speckled patterns, making it an attractive addition to reef tanks.

Sexual Dimorphism:

• Males and females appear nearly identical externally, as urchins do not show obvious sexual dimorphism.

• Juveniles are smaller, lighter in coloration, and develop stronger spine density as they mature.

Size & Tank Requirements:
They reach about 3–4 inches in diameter and should be housed in aquariums of at least 30 gallons.

Habitat Needs:
Provide plenty of live rock for grazing, stable structures to climb, and areas of open sandbed for movement. They may also appreciate hiding spaces in rock crevices during the day. Stable water parameters are essential:

• Salinity: 1.020–1.025

• Temperature: 72–79°F

• pH: 8.1–8.4

A secure lid is recommended, since urchins may dislodge rocks or equipment as they move, though they do not jump.

Diet:
Shortspine Urchins are primarily herbivores and detritivores, feeding on algae (film algae, coralline algae, macroalgae), biofilm, and detritus. In captivity, their diet can be supplemented with dried seaweed (nori), algae wafers, and occasional microalgae-based foods.

Care Note:
While hardy and useful for algae control, they may scrape coralline algae and occasionally knock over unsecured corals or rockwork. With proper care, the Shortspine Urchin makes a practical and fascinating addition to the marine aquarium.

algae, etc.], and with proper care this fish makes a standout addition to the aquarium.

International Aquatics Quarantine & Guarantee: All fish are checked by marine vets, given a formalin bath, and held for 14 days in copper-treated systems. We feed Selcon-soaked food with Kanaplex and Metroplex during quarantine. Unless marked, all livestock comes with our 15-Day Guarantee. You will receive a video of your fish eating before shipment. On request, we also send photos/videos after arrival at IA. Some species are import-to-order (3-10 business days). Many common species are already cleared or near the end of QT.

Several species will be import-to-order and may take anywhere from 3-10 business days to secure. Once your fish is secured, you will be notified, and the quarantine process will then begin.