Aquarium Livestock Pet Care Guides

Sea Urchins

Natural Habitat

Indo-Pacific, Atlantic

Tank Temperature




Specific Gravity



Herbivores; will consume detritus and algae; supplement with seaweed if algae is lacking; some may also feed on leftover food in the tank, invertebrates, sponges, and dead fish. Use a rubber band to secure a piece of dried algae to a rock to make grazing and clean-up easier.


Generally peaceful; may harm inverts as they move around while grazing; several species have venomous spines, particularly Longspine Urchins, Fire Urchins and Flower Urchins.


Community, Reef, and Invert Safe, with caution. Should NOT be kept with fish othat will prey on urchins, such as triggers; best kept one or two to a tank.

Species Overview

Urchins are grazers that will roam about the tank searching for food and algae on the substrate and rockwork. Most will not actively eat corals, but some delicate corals may be damaged if the urchin crawls on top of them or knocks them over. Urchins may also occasionally feed on coralline algae that some aquarists may be trying to promote. If algae levels in the aquarium are low, urchins can be fed by attaching algae sheets to a piece of rock with a clip or rubber band.

Some urchins are venomous, but most species are harmless to aquarists. The most common injuries from urchins happens when the aquarists bumps against an urchin and gets poked by its spines. Spines can become broken off in the skin, especially with thinner-spined urchins, so always take care around your urchin to avoid injuring it or yourself. Urchins are sensitive to water quality and changes in conditions. They will often be one of the first organisms to show signs of stress in an aquarium. Acclimate new urchins carefully and avoid drastic changes in temperature, pH, salinity and other water parameters.

Recommended Items

Live Rock
Water Test Kits