Blenny and Pistol Shrimp

[Plauri55]

About a month ago I added a pair of Wheeler's gobbies and a pistol shrimp to my tank. Sold as a "bonded" group. Needless to say, once in the tank the gobies had nothing to do with the shrimp. In fact the two gobies hardly hang together.
Didn't see the pistol shrimp for about 3 weeks. Then last night, just before lights out I saw my Tailspot Blenny digging a burrow under a small piece of live rock. When I looked closer I saw the pistol shrimp in the burrow also cleaning out sand. A short while later the Blenny was tucked down by the hole guarding it.
Is this an unusual behavior? I'm fairly new to this hobby and never heard of a Blenny pairing up with a shrimp.

 

[eatbreakfast]

Pistol shrimp will tolerate a variety of fish in their burrow, but they don't form the same symbiotic relationship or get any sort of protection, as it would with a watchman goby.

 

[Plauri55]

Thanks for the info. It's just so much fun watching all the interactions in the tank.