Missing urchin

[Tx Medic]

I recently got a longspined urchin and after two days it disappeared into the rocks and I have not seen it for about 6 days now. The tank is a 75 gallon w/20g diy sump. I checked everywhere I can get to and cant see it anywhere. Any ideas.

 

[big blue]

I dont see mine for weeks at a time they tend to hide during the day look for it when the light are out!

 

[Tx Medic]

Urchin is still MIA I am going to break out the flashlight tonight and try and catch a glimpse of him tonight.