Diadema Urchin with Puffer and Trigger

[Feet4Fish]

I have long wanted a long spine black urchin for my tank. I have a porcupine puffer and niger trigger in this tank. Neither have ever shown aggression toward snails or hermits. Live Aquaria mentions this urchin good for aggressive tanks. What is everyone's experience? Don't want a forgone urchin massacre.

 

[Maritimer]

I've seen video of queen triggers taking out Caribbean Diadema urchins, but that doesn't mean a niger would do it. I've got a tuxedo urchin in with my blue jaw trigger, and no incidents to date . . .

~Bruce