Pencil Urchin

Updated August 6, 2019
Author: Mike - FishLore Admin
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The pencil urchin is often picked up by hobbyists that want to add them to their clean up crew. This urchin will graze on algae, sponges, tunicates and does a decent job. However, they may also eat calcareous coralline algae and macro algae as well. The pencil urchin will eat meaty foods too and some hobbyists have reported that they have caught them munching on ornamental shrimps and crabs. You can usually find them online for $10 to $20 a piece and they are often on the small side but they can get up to around 6 inches (15 cm) when fully grown.

They may knock over loose frags so keep that in mind if you put one in your reef tank. They will also eat the items mentioned above so you may want to take a pass on this invert if you have a reef tank setup. A fish-only type tank setup of 30 gallons or more with lots of live rock for them to graze on is decent to start with. They are mostly nocturnal so you may not see them out and about when the lights are on.

Eucidaris tribuloides

Pencil Urchin Care

Scientific Name : Eucidaris tribuloides

Common Names : Mine Urchin, Primitive Sea Urchin

Care Level : Easy

Life span : several years

Size : 6 inches (15 cm)

pH : 8 - 8.4

Temperature : 72°F - 80°F (22°C - 27°C)

Specific Gravity : 1.020 - 1.026

Origin / Habitat : Caribbean

Reef Safe? : Not considered reef tank safe

Temperament / Behavior : Peaceful algae grazer

Breeding : Sorry, don't have info on breeding them at this time.

Aquarium Size : 30 gallon plus recommended

Tank Mates : They should be able to take care of themselves and most fish species will leave them alone, except for triggerfish. Triggers have been known to be able to flip them over to get at their softer undersides.

Diet / Foods : They will graze on algae (including calcerous algae), macro algae. May eat sponges and tunicates as well. Clams and mussels on the half-shell and other meaty marine origin foods will be accepted as well.

Tank Region : All over the live rock

Gender : There are no definite ways to distinguish males from females.

Similar Species : Marine Invertebrates

Reef Invertebrates Guide by Calfo and Fenner
Marine Invertebrates by Shimek

Site References :

More Saltwater Invertebrate Profiles
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