Are long spine sea urchins poisonous and can their stings do much harm?
The spines are sharp and you could stab yourself with them, but the animal moves very slowly. You would have to be very distracted to do this to yourself. They are not poisonous but they are the only urchin with venemous hollow spines and there are bacteria living on them that should be able to cause some problems if you don’t clean the puncture. The mouth is where there is digestive fluid that could hurt you. If you held it long enough, the urchin could expell its stomach and begin digesting your skin. These are the kinds of things that generally only happen to bored college students. As long as your saltwater tank is not in a dorm room or fraternity house, there should be no danger to you or the fish in the tank. They will eat algae, and if you put them in a reef tank, there is a risk they would eat something you don’t want them to. The ideal tank for them is a sand substrate with no or only a few rock mounds. When you buy them be sure each one is bagged separately and double bagged.
