As many years as I've been in this hobby, Scorpionfish have always held a special place in my heart. They are absolutely amazing fish and many different species can be housed together, with no ill effects.
I have to say, though...I'm very, very impressed with you, being able to keep an Ambon alive. I'm not sure how long you've had it, etc. but they never, ever have a decent lifespan, in captivity. When I say that, I mean I've seen 50+ different specimens that have never lasted more than 2 weeks. Whether it be to not eating, etc. I've never seen them last.