This morning I went to the garage to feed my 12" Mbu and after I took the blanket of the tank I saw that he was not in there. *****. I started looking around and could not find him but after I removed some plywood that is leaning against the wall behind the tank I finally located him between a large leftover piece of marble from our kitchen counter and the wall. Thinking that he was dead since he was covered in dirt and didn't look like he was breathing I grabbed a net moved some stuff around and was finally able to reach him. I tried to scoop him in the net to throw him out and to my surprise I hear noise. He is starting to make a sucking noise to suck in air and blow up. Finally after a few tries I get him into the net fullly blown up by now and stick him back into the tank. After a few seconds he starts to deflate and sinks to the bottom of the tank. He is covered in dust and looks like crap but to my surprise his fins start wiggling and he slowly swims to his corner and sits on the bottom. I stuck my hand in and wiped the dirt off of him gently and he ate a shrimp 5 minutes later. Now I don't know how long they can survive out of water but I can assure you it's at least 10 minutes. I'll keep an eye on him over the next few days to make sure he doesn't get any skin infections and I already escaped proof his tank now with eggcrate in the back where he got out.