I'm cleaning and installing the bubbles today in the 20g. I got all the fish into a bucket except for Wasabi who is missing. I THOUGHT I saw him this morning at breakfast, but the only place he could be now is in the castle. I've shaken it (I know, not good, but what else can I do?) and tapping it. Nothing. I also shined a light inside but can't see into every corner. What can I do? I need to take the castle out of the water in order to put the tubing in. Did he die in there? Help! I don't want to keep the fish in the bucket overnight so I need to finish it today!