rrasco...the ray was probably sleeping. She's either REALLY easy to see swimming around, or she buries herself in the fine sand and almost completely disappears. When we first got her, I had a couple of times that I came home from work and started looking on the floor outside the tank. I thought she must have jumped out or something because I didn't see her anywhere! Then, I'd spot her spiracles and breathe a sigh of relief. But, buried...she's nearly invisible..lol