We have a bonded pair in our tank and they're super fun to watch. It's my understanding that if one dies you can just replace it, it may or may not bond with the surviving goby/shrimp. Worst case they ignore each other. Ours are in a 90 gallon tank with a pair of clownfish, kole tang, blue tang, mandarin, cleaner shrimp, and blood shrimp. They don't bother anybody. Occasionally if a snail or hermit crab gets too close to their little tunnel the pistol shrimp will come out and push them away. They're easily one of my favorite things in the tank.