Collector urchin

Care at a glance

Overview

The collector urchin is a peaceful grazer and one of the more effective algae-control animals a reef tank can hold. It is easy to care for.

Caring for the collector urchin

Give the collector urchin a mature tank of at least 20 gal (75 L), with live rock to forage over. Leave enough open floor for an animal that can reach 5.9 in (15 cm) across.

Keep the water at 75 to 81°F (24 to 27°C) with a pH of 8.1 to 8.4. Like other urchins, it needs a slow drip acclimation, since sudden swings in salinity or pH can kill it outright.

It grazes constantly, working over algae day and night, so it needs a steady supply to work through. If the tank's algae runs low, clip on dried seaweed so it does not start looking for other food sources.

The collector urchin is peaceful and reef safe, and it leaves coral tissue alone. A big specimen can still bulldoze small frags or shift light rockwork while foraging. Secure the aquascaping and keep an eye on anything not glued down.

Good to know

The collector urchin, Tripneustes gratilla, is a regular urchin in the family Toxopneustidae. Its dark purplish to black test is covered in short white spines, sometimes tipped in orange. It is one of the larger reef urchins in the trade. True to its collector name, it picks up loose shells, rubble and bits of algae to pile onto its spines as camouflage. It is also sold as the pincushion urchin or the Halloween urchin.

In the wild

Collector urchins range across the Indo-Pacific, from East Africa and the Red Sea to Hawaii and French Polynesia. They live on open reef flats, seagrass beds and rubble, from just below the surface down to about 30 m. Juveniles favor rocky cover, while larger adults move out onto more open ground to graze. They are voracious grazers of algae and seagrass and can strip up to half of a seagrass bed's growth during peak feeding season.

Common questions

Related species

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• 

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