I have a long spine sea urchin in my tank that I've had for a couple months. A friend of mine tore down his saltwater tank and gave me some livestock. One of the things he gave me was a blue tuxedo urchin. The question is. Can both urchin stay in the same tank?
what size tank do you have , I had different urchins together with no problems but I have a big tank
I would say any tank 3ft long or larger would be ok anything smaller I would question as they need there space