I just wanted to add in about the caves up there. The little holes reminded me of an accident I had with one of my female bettas. Small holes, they get stuck in. I had this castle that, I didn't know had an opening going up into the top, which had a hole, the size of the tip of a finger at top. She tried to get out, got stuck and died. So, when I saw the cave thing--if you have that in with bettas, just be careful. Bettas will try to get through any size hole and not be able to at times.
Just wanted to share so no one has the accident I did. :(