Re missing goby

[seashells]

Hi all<

Picked up a pair gobies over the weekend. They were together in the same tank for a couple weeks at the lfs. The first couple days home they were visible together doing their thing. They built places under this rock. Now one is missing. They were sleeping under a rock. The remaining goby has covered all the entrances leading under the rock. It now seems to be guarding the rock. Its been 2 days now since we have seen them together. Tank is covered. Any ideas?

Shellie