Mediterranean purple urchin

Care at a glance

Overview

Peaceful and undemanding about food, but it is not a reef tank animal: it needs cool water, and in any tank it will eat every macroalga and seagrass and scrape the coralline off the rock. Keep it in a temperate setup with other Mediterranean or north-east Atlantic animals, feed kelp, dried seaweed, and algae wafers, hold the water at 12 to 24 C with high oxygen and full marine salinity, drip acclimate it, and never use copper. It does not tolerate low salinity. It is not collected for the US aquarium trade, so you will only meet it in European temperate tanks or as seafood.

In the wild

The Mediterranean purple urchin lives on rock, in boulder fields, tide pools, and seagrass meadows across the Mediterranean and along the north-east Atlantic from western Scotland and Ireland to Morocco, the Azores, and the Canary Islands, mostly at 0 to 20 m. In exposed spots it bores cup-shaped pits into soft rock with its teeth and spines and lives in them. It is a temperate animal: winter water where it is common runs 10 to 15 C and Mediterranean summers reach the mid 20s, so a home tank needs 12 to 24 C and usually a chiller, plus rock, strong flow, and 150 liters or more. Water stays at pH 8.1 to 8.4.

Good to know

Paracentrotus lividus is a regular urchin in the family Parechinidae. The test is flattened and reaches about 7 cm across, with spines that are usually purple but can be brown, olive, or green. It eats red, green, and brown algae and seagrass and is one of the main grazers of Mediterranean shallows. It is the edible urchin of Mediterranean cooking, harvested for its roe from Ireland to Greece and raised in hatcheries, and some fished populations have collapsed. Heat kills it: field and lab work in the eastern Mediterranean found mass mortality once water passed about 30 C.

Common questions

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