Can a watchman goby get stuck in his cave?

[spiraling]

Hey all,
My goby has a shrimp buddy. The shrimp usually blocks them in for the night, then very diligently digs all day while the goby keeps guard. The goby is pretty much always out for feeding time. Then I didn't see the goby at all for two days, and I didn't see any recent digging. I got a little concerned and dug out the main entrance to the complex, and within minutes the goby was out and looking for food. I saw the shrimp the next day.

So I'm not sure what happened. I'm guessing maybe the shrimp was molting and didn't want to come out? Has anyone else noticed this? Should I be concerned that my goby might get trapped in their cave?

 

[Mayja]

If your rocks are resting on the sand and the shrimp dug too deep, they may have had a partial collapse that could have trapped them. I've always been told to have my rocks sitting on the glass, then add sand to prevent my digging fish/inverts from this fate.

 

[spiraling]

My rocks are on the glass for this very reason. I don't think there was a collapse. It was more like the shrimp took a few days off. Maybe it was a paid vacation.

The shrimp has dug in the sand not under rocks and I've seen the tunnels collapse. I was concerned about the shrimp being buried in the sand, but he was fine and working just as hard the next day. I'm guessing this is something that happens often enough in the wild and they are prepared.

 

[Oxylebius]

So what happened? Did you find the fish and shrimp?