I would cycle the tank with damsels and once it's ready, put the dragon in. The dragon will take care of the "damsel problem"
. They're not cheap, but they are worth the money and long lived. Aquacon has a Japanese Dragon. Same thing
Eels, saltwater fish aquarium - Aquatic Connection
The Hawaiian Dragons go for about $500-600. 20-30 year life span. Pretty friendly believe it or not. My brother had one that I could pet.