Diadema savignyi

(Audouin, 1809)

Banded Long-spined Urchin

Range: Indo-West Pacific Ocean: Red Sea to Australia.

Size: 10 inches (25 cm)

Natural Environment: Inhabits reef areas and found on rock and rubble areas covered in algae.

General Husbandry: Occasionally seen in the home aquarium trade.

Hides during daylight hours and feeds at night.

Best maintained in large aquariums having areas/caves it can hide during daylight hours as its very sensitive to light.

Can be a real bulldozer and annoy corals in reef aquariums, therefore may be better housed in fish-only aquariums.

Has a desire for calcium carbonate, which is a mainly coralline alga. Therefore can be given pieces of cuttlebone or algae blocks to prevent it from consuming coralline algae, which most aquarists cherish. Place in aquarium in early evening hours.

In aquariums somewhat devoid of algae, small plaster-of-Paris feeding stones that contain seaweed and algae can also sometimes help lengthen lifespans of these urchins in aquariums.

Consumes huge amounts of algae! Sheets of Nori weighted down with small rocks may also help keep this species well fed.

Taxonomy:

Kingdom: Animalia

Phylum: Echinodermata

Class: Echinoides

Order: Diadematoida

Family: Diadematidae

Genus: Diadema

FYI: Vulnerable to sudden salinity/specific gravity changes.

Has sharp hollow thin spines that break easily and contain mild venom - its poisonous mucus may be painful for a few hours, but not fatal to humans, but removing a spine in your hand is no fun! Been there, done that!

Triggerfish and large wrasses eat urchins.

Experience Level: Intermediate

Diet: Herbivore

Aquarium Environment: Reef or fish-only aquarium

Coral Safe: With caution

Fish Safe: Yes

Invertebrate Safe: Yes

Acclimation Time: Sensitive to specific gravity/salinity changes, therefore be sure to adjust the bag's water to that of the aquarium in which it will be placed by slowly adding small amounts of aquarium water to the bag every few minutes. In most cases, this process should take at least 15 minutes.

Aquarium Hardiness: Moderately hardy

Temperature Range: 72 - 83°F (22 - 28°C)

Minimum Tank Size: 150 gallons

Specific Gravity: 1.023 - 1.025

pH: 8.0 - 8.4