Mystery sand hole?!?!

[zoagro]

This keeps happening, I only have 2 clownfish and a yellowtail damsel. All of my rock was from dry rock except for one piece so I don’t know what it could be because that doesn’t seem like enough for a hitchhiker like a mantis shrimp. I have a tiger conch but this seems like a lot for him to kick up.

 

[officialreefbros]

Could be the yellowtail trying to dig a cave!

 

[zoagro]

Could be the yellowtail trying to dig a cave!

Is that good or bad? I’m still deciding if I like or hate that fish… I got it for $3 from my LFS

 

[officialreefbros]

It's normal behavior