Shade. LOL I was only kidding about that, but when he sleeps under there it looks like that is what he is trying to do. The lights go off at night. In fact most of the time the light in the tank is off since the room gets alot of natural light. Also whenever I turn the hood lights on he thinks it's dinner time.
I highly recommened silk plants. They are alot safer then plastic. With Bettas we have to watch the decor. When I first set up his tank I had a big castle with all these passage ways, UB loved it and played in it all the time, but his tail fin was getting tattered so I had to exchange it for the cave. At first he was peeved and wanted the castle back it took him several days untill he got curious and decided that spelunking was better then playing dungeons & dragons (-: