I got a diamond gobie yesterday and it was doing fine, this morning it looked like it was dead.. It was covered in sand kinda looked like it was stuck under the rock, it wasn't moving for awhile so i thought i would see if it was dead.. It didn't move when i was waving my hand in front of it but then when I started moving the rock from ontop of it, it shot out and started swimming around.. Is this normal behavior of gobies?