|Latin name||Heterocentrotus mammillatus|
|Local name||Pencil urchin|
|Family||Echinoidea - Heterocentrotus|
|Origin||East Indian Ocean|
|Max length||30 cm (11,8")|
|Minimum volume||400 cm (106 gal)|
|Suitable for aquarium||Suitable for most aquarium|
|Reef safe||Often reef safe|
Microalgea (Eg. spirulina)
Macroalgea (Eg. seaweed / nori)
Small crustaceans (Krill, mysis, artemia...)
This species needs good hiding places, for example, between live rocks.
This species is nocturnal and therefore the most active when the light is dimmed or turned off.
Sea urchins are often used to keep various algae at bay.
They are very effective algae eaters, and will eat anything from coralline algae to green hair algae.
Sea urchins must not be kept in an aquarium with few algae, as they may starve to death.
Sea urchins should be acclimatized slowly, due to sensitivity towards changes in salinity.
Ronald L. Shimek. 2004. Marine Invertebrates (PocketExpert Guide) - TFH Publications / Microcosm Ltd. - (English)
Ronald L. Shimek. 2003. Sea Urchins, A Testy Subject - Reefkeeping Magazine - (English)
Bob Fenner. Some Spines Now! Sea Urchins (and Sand Dollars), the Echinoids, Pt. 1, Pt. 2 - Wet Web Media - (English)
"Minimum volume" indicates the size of the tank needed to house this species under optimal conditions.
This is based on a medium size animal, which you want to keep for several years.
It might be possible to keep smaller specimens for a limited period in a smaller tank. A larger tank might be needed for fully-grown specimens.
"Hardiness" indicates how resistant this species is to disease and how well i tolerates bad conditions in general.
Some species doesn't handle transportation very well, but that doesn't mean that the species isn't hardy under the right conditions.
In this case, a "normal" aquarium is a reef aquarium with mixed corals or a fish only aquarium with an approximately salinity of 1.026 (sg) and a temperature close to 26°C.
Species requiring more than a 4000-liter tank are considered not suitable for home aquarium.
Special aquariums may cover tanks with low salinity, sub-tropical temperature, deep sand bed, sea grass etc.
Always reef safe: No sources indicate that this species will harm corals or other invertebrates.
Often reef safe: Only a few aquarists has reported problems keeping this species with corals and other invertebrates.
Reef safe with caution: This species may be a threat to some types of invertebrates.
Reef safe with luck: Most specimens will harm corals and/or other invertebrates, but you might be lucky.
Not reef safe: This species is a threat to most corals and/or other invertebrates.