My pseudochromis orchid dotty back has been missing for a day or so. She shares the tank with only one clown, a Blue eye kole tang, and a large snail. The other fish get along good with her, and my parameters are pristine. Is it normal for this fish to just up and decide to disappear into the rock work for a while? If this is normal, how long do they do this for? Tank is 35 gallon covered. She usually is out in the display with the other fish swimming around most of the day.