Using its spines as protection, urchins can be used in tanks with predatory fish, that would otherwise eat snails such as puffers. (Triggers however are smart enough to flip them over and attack their underside).
The Pencil Urchin, is a multicolored urchin with dull spines, making it safe for touch tanks. This particular urchin will be most active at night, and can grow to 3 inches in diameter
They devour algae, especially hair algae, as well as more complex and possibly decorative macro algae and are not marine planted tank safe, they are considered reef safe though. They should be given plenty of live rock to graze on, and should be kept in tanks over 30 gallons.
Urchins scratch acrylic, and they will probably eat some coralline. They will eat any edible macros they come across, and may remove tunicates byrozoans and other small sessile inverts from your live rock.
This species requires Express Mail and does not qualify for free shipping.