So another update! I put Ragnarok into the tank with the four danios. Everyone is alive, no one is hurt and its been 2 days now. He does give them a chase when they go near his silk plant that he's claimed but otherwise he doesn't care. I originally got him from a tank with other fish, and I was worried he'd be spoiled all by himself... but nope! So far so good! Just for a laugh here's a picture of him angrily glaring at me from the bag.
Another question though, when I go near the tank he will sit at the bottom and look at me. When I walk away to where he can't see me he will swim and explore.. any ideas on that?