Basslet Weird Behavior. Ideas?

Hey All, So I recently got a Black Cap Basslet. It's in a tank with a Maroon Clownfish, Yasha Goby with Pistol Shrimp and a little yellow Clown Goby. Everyone gets along just fine. The clown is not that aggressive and rather quite passive. Same goes with the Basslet as it was the last fish added.



My question is this... Recently, about one week. The Basslet has been swimming up to the clown goby, opening its mouth and putting it on the side of the clown goby. They sit there for about 2-3 seconds and then continue with their lives. The clown goby doesn't seem afraid, doesn't run and hide. After the basslet stops, the clown goby just continues as if nothing has happened. Not sure what is going on. I notice it after all the fish have eaten.



Any ideas guys?



Thanks!