Did my Bicolor Blenny kill my Yash Goby?

I have a 50 Gallon Reef tank I am setting up for seahorses. I have 2 Firefish, a 2" Bicolor Blenny and I HAD a Yasha Goby/Pistol Shrimp pair. The last fish to go in was the Bicolor, who shortly thereafter took up residence for a couple days in the same rock/burrow as the Yasha Goby and Tiger Pistol Shrimp. From that day on I have not seen the Yasha. I can see, however, that the Pistol Shrimp is alive and well in the burrow where he stays. Is it possible that the Bicolor, who now never goes in that burrow, killed the Yasha Goby? The Yasha used to be out in front of her burrow with the Pistol Shrimp nearby inside. I have not seen the Yasha in 2-3 weeks, since the Bicolor first came into the tank. Thoughts?

Do I dare add another Shrimp Goby? If so, what would be the best kind to add?